I have always found the hardware mouse is compatible with any DAW or VST.  Just sayin! 

@OP
 
The situation with having to change (update) dlls after updating Sonar isn't so different than Adobe After-Effects users having to reinstall extensions after updating After-Effects.
It's really not that time consuming.
 
BTW, No matter which DAW software you choose, you're going to make some degree of compromise.
They all have strengths/weaknesses.
It doesn't hurt to have a couple different tools in the toolbox.
The "perfect DAW"... by committee...
 
Another thing to think about:
A lot of controllers have come/gone over the past 20 years.
How many actually survive and are supported for a significant period of time?
If you were running the company and had to choose where to spend resources, would third-party MIDI controllers (that likely won't be around 2 years from now) be a high priority?
In today's economic climate, tough choices have to be made.
Mackie Control is somewhat of a "standard"... but it's not a strict standard (thus the issues with certain controllers including Machine/Studio).
 

abacab
I have always found the hardware mouse is compatible with any DAW or VST.  Just sayin! 

Unless you're using Mixbus on a Mac. Mixbus requires a three button mouse, Mac mice and trackpads are very good and have lots of gesture controls etc. but not the third button Mixbus wants. Luckily a basic three button mouse is very cheap these days.

Jim Roseberry
A lot of controllers have come/gone over the past 20 years.
How many actually survive and are supported for a significant period of time?

This is why I much prefer controllers and MIDI interfaces that are Core MIDI/Windows class compliant over ones which require specific drivers from the manufacturer. All too often the product gets dropped from the driver update line a long time before it wears out. And controllers haven't changed much really over the last 20+ years, and even the new controllers such as the Roli and QuNexus, which make expressive playing much easier than using a keyboard plus a foot controller and a breath controller, still rely on basic MIDI for their functions. Even polyphonic aftertouch still hasn't taken off even though modern computers are much more likely to be handle the huge amount of data it generates than those of less than a decade ago.

Same with software synths and plugins - at some point the OS or DAW is likely to get an update that means they don't work any more, or the coders go bust and it becomes impossible to authorise their products. It's the downside of the digital revolution in a way, and those of us who are old enough will have had a bunch of computers, printers, scanners and even cameras that still work but we "retired" them because at some point a new version was much faster, better, or you couldn't get ink for that printer any more and so on.

Jim Roseberry
If you were running the company and had to choose where to spend resources, would third-party MIDI controllers (that likely won't be around 2 years from now) be a high priority?

Well, they wouldn't be for me if I was running the company. I'd make sure my software was compatible with the industry's most common "standards" and let the hardware manufacturers worry about making sure their product actually met that standard. Though if I was a hardware company as well as a software one I might produce controllers designed to work seamlessly with my software. But Roland did that when they owned Cakewalk and we all know what happened to their Sonar-dedicated line of controllers.

tlw
Unless you're using Mixbus on a Mac. 

First problem.

tlw

Jim Roseberry
If you were running the company and had to choose where to spend resources, would third-party MIDI controllers (that likely won't be around 2 years from now) be a high priority?

Well, they wouldn't be for me if I was running the company. I'd make sure my software was compatible with the industry's most common "standards" and let the hardware manufacturers worry about making sure their product actually met that standard. Though if I was a hardware company as well as a software one I might produce controllers designed to work seamlessly with my software. But Roland did that when they owned Cakewalk and we all know what happened to their Sonar-dedicated line of controllers.

I don't expect special coding for each specific make/model.  It sure would be nice to have a straight-forward, robust mapping capability though.  Simplicity and completeness for the user.  I have one DAW that excels at this with dead simple context sensitive mapping to boot.  Unfortunately, there are other things it doesn't do as easily as SONAR.

Ham N Egz
Go to GS/KVR/etc and read the negative posts about Sonar AND our forums

Go there and read posts about anything and you come away wondering if anything works at all or any maker of anything ever utters a true word. Analogue synths and guitar gear frequently gets slated for being "digital" when it's no such thing, and the old whatever it is is you can't buy any more is always praised by someone as so much better than the current version of the same thing. Even if the current one is exactly the same as the old one.

The signal to noise ratio can be very low at times.

How about a Mackie control app for Windows that you could just run from a touchscreen as 2nd monitor?  Sort of like a control pad app for iPad, but completely integrated with Windows and Sonar?
 
No hardware development investment required, just some creative software engineering.  And a virtual MIDI cable.

abacab
How about a Mackie control app for Windows that you could just run from a touchscreen as 2nd monitor?  Sort of like a control pad app for iPad, but completely integrated with Windows and Sonar?
 
No hardware development investment required, just some creative software engineering.  And a virtual MIDI cable.

For some reason that does not exist... I guess no market. I have found only one App in that direction. Logically, who is going to use windows tablet for the purpose? Cheap tablets can also run Andoroid, expensive can run Sonar.

abacab
How about a Mackie control app for Windows that you could just run from a touchscreen as 2nd monitor?  Sort of like a control pad app for iPad, but completely integrated with Windows and Sonar?
 
No hardware development investment required, just some creative software engineering.  And a virtual MIDI cable.

Maybe http://ctrlr.org/ will get you a step or two in that direction.