Welcome to the forum!

The two core elements I see being discussed most often are:

1. WHAT can an instrument do? That includes: a) what functionality does it have and b) what limitations does it have

2. HOW EASY is it to use the instrument's functionality to do what you want to do? That includes both on-board (the user interface) and off-board (connecting to computers or other instruments).

I think the MPE (MIDI Polyphonic Expression) you mention falls into a third category: capturing what you do in a standard, and detailed way.

All of those are 'musician friendly' in some areas and 'musician antagonistic' in others.

MPE is the easiest to address since your comment sums it up fairly well:

I understand that MPE/Midi 2.0 gives all of this midi control on a key per key basis

The MPE spec (adopted in 2018) is available here but for MIDI Association Members only:
https://www.midi.org/midi-articles/midi-polyphonic-expression-mpe

There is a good summary about halfway down the page but it starts with this:

The MPE specification aims to provide an agreed method for hardware and software manufacturers to communicate multidimensional control data between MIDI controllers, synthesizers, digital audio workstations, and other products, using the existing framework of MIDI 1.0.

These proposed conventions define a way of distributing polyphonic music over a group of MIDI Channels, making multiple parameters of different notes separately controllable. This will enable richer communication between increasingly expressive MIDI hardware and software.

Briefly, what is defined is as follows:

--- Wherever possible, every sounding note is temporarily assigned its own MIDI Channel between its Note On and Note Off. This allows Control Change and Pitch Bend messages to be addressed to that particular note.

--- A Registered Parameter Number is used to establish the range of Channels used for sending or receiving notes. Two messages control the division of MIDI Channel space into sub-spaces called Zones, so that multi-timbral playing is still possible using only one physical MIDI interface.

--- When there are more active notes in a Zone than available Channels, two or more notes will have to share the same Channel. Under such circumstances, all notes will continue to sound, but will no longer be uniquely controllable.

--- Each Zone has a dedicated extra Channel, called the Master Channel, which conveys common information including Program Change messages, pedal data, and overall Pitch Bend. These messages apply across the entire Zone.

(The MPE specification also defines how to handle Pitch Bend, Aftertouch and CC messages to provide maximum interoperability.)

So MPE is all about capturing musical expression data in a standard, portable format.

IMO neither Montage/Modx nor Eagan Matrix targets that area. Yamaha certainly doesn't support MPE yet. And it barely provides ANY direct support for the current MIDI spec in terms of allowing the user to manipulate MIDI content.

The other area you mentioned was comparing Montage to the Eagan Matrix.

I know the Montage/Modx doesn't make any MPE or Midi 2.0 claims but Motion Sequences + Control Assign + Aftertouch gives as much MPE as is practical.

I don't agree with that assessment at all. There isn't any 'per note' capability in the Montage/Modx. There is only bare minimum 'per envelope' capability.

It isn't really possible to manipulate/control entire sets of related parameters the way that MPE allows and the UI provided is wholly insufficient to support what is allowed.

Re the Eagan Matrix: http://alex4.de/images/manuals/EaganMatrix_usermanual.pdf.pdf

Limited to a brief review of that doc (and no personal experience) my impression is that the technical possibilities are impressive in terms of the degree of freedom you have to control things.

But I would expect there to be a pretty steep learning curve before you could really be productive.

And, as with the Montage/Modx, definitely NOT 'musician friendly'.

I understand that MPE/Midi 2.0 gives all of this midi control on a key per key basis, but in real world music scenarios what Motion Control offers accomplishes the same thing and from looking at the Eagan Matrix editor, The Montage/Modx approach is far more musician friendly!

Apples and Oranges comparison.

MPE is a 'language' for expressing musical content. It doesn't address at all how to expresss things in that language.

Montage/Modx have some ability to express musical things but only in a SUBSET of the MPE language - that is, only using the original MIDI spec. There is NO 'per key/note' control at all.

for practical purposes Motion Control's 24 parameters, motion sequence lanes being able to be used as sources for controllers will give the player just as much practical expressivity as what's happening on the Osmose.

I don't consider the Montage/Modx anywhere close to providing the degree, or the amount of control over parameters as what the matrix (and other synths) can provide.

You keep mentioning motion sequence but may not realize just how limited it is. Read through this article by Bad Mister and note several areas where those limitations are mentioned. I'll just list a few examples:
https://yamahasynth.com/learn/montage/mastering-montage-12-motion-sequence

1. There are 16 parts available but only 8 are under keyboard control

2. Each part can have up to 4 lanes BUT only 8 lanes are available at a time - so you can't even use 1 lane per part

3. You can define 8 motion sequences but only ONE is active at a time for a part. There are 8 SETS of sequences and you can switch between them

4. You can't really assign a cohesive/coherent set of parameters to a control. For instance there are three types of envelopes: Pitch, Filter and Amplitude and they each have parameters similar to those used to control ADSR (attack, decay, sustain, release). It isn't possible to assign and control all three of those envelopes the way you can with other synths.

The recently introduced pattern sequencer comes closer to providing some meaningful control but it is both limited and not well suited to targeting individual sets of parameters such as those envelopes I mentioned.

For a visual demo of the type of dynamic control the Montage/Modx lack take a look at one of the new Super Morph performances available:

1. Load the Hydra Drone - this is a super morph performance
2. Edit part 1 operator 1
3. Go to the Level tab - here you can see the ADSR type of parameters I mentioned
4. Move the Super Knob around and watch how almost every parameter changes
in real time.

That is the sort of manipulation/control I am talking about for 'targeted control' of a set of related parameters.

The problem is that you can't really create that sort of thing manually. It didn't exist at all before Super Morph was introduced. And the morph functionality implemented doesn't provide the UI or control needed to produce specific, desired results.

Other synths, and the matrix let you do things like that as MACROS that can be stored and then combined in any desired combination. They also let you link specific macros to specific and different targets so that you can build sounds from the bottom up.

The closest you can come on the Montage/Modx is to use a convoluted process to try to mimic what those other synths and matrix can do:

1. create a very limited, targeted, super morph set
2. twirl the super knob while recording all of those dynamic parameter changes to a pattern sequence
3. modify the super morph set to target a different set of parameters
4. twirl and record the new set as a new pattern
5. and so on

That would result in having a BASE set of patterns that essentially consist of multi-track MIDI that contains a large number of control change commands.

Then you can 'mix and match' to combine those separate patterns and/or chain them together to create the support elements needed for a performance.

That method isn't even 'programmer friendly' let alone friendly to a musician.

Very Generally Speaking:

Motion Sequencer and SuperKnob are well suited to slower, time based evolvements of changes, over durations larger than a couple of beats, up to many bars long.

They are not well suited to the tight envelopes we're used to exploiting with rapid control deviations - which is those thing that MPE and the Osmose specialise in.

One of the key indicators of this, if you don't want to lose your mind discovering this (as I did), is the lack of velocity and aftertouch mappings to the Motion Sequencer's and SuperKnob's qualities. The other is that there's far many more multipliers of Motion Sequencer timings than their are dividers... you can "divide" the rate by 75%, 66% or 50%. But you can multiply it by anything up to 6400%

IOW... Motion Sequences and the SuperKnob are great for evolving changes, over many notes. And are. They're best thought of as "hands free", inter-connectable knob twiddlers, whereas MPE via keyboards with multiple axis of responsiveness are better thought of as enabling envelope modifications at time slices of individual notes.

There is a somewhat regular user of this forum high up in the delivery list of the Osmose and may already have his.

I didn't see that coming...