Interesting post, and some of the comments.   
 
Fundamentally, there are two giant issues that remain, and the OP and comments said them:
 
TOO MANY CLICKS for some things, can not be eliminated no matter how familiar you are with the interface.   Say that again?  TOO MANY CLICKS.   About as simple as can be said. 
 
Too many potential terrible, work-upsetting consequences for a bad key press.    Especially UI consequences, that CANNOT BE UNDONE.      Granted, this one is gradually learned, for sonar and for other software .. and one maps away bad keys gradually.   But why o why make defaults that do wild unwanted things? 
 
I wish people like XXX would never respond to this kind of post.  We know you adore sonar, but please, XXX,  don't try to eliminate the problems that real people face by chiming in on every post and claiming that anyone who posts a pragmatic criticism is a person that's not flexible, up-to-date, attentive, realistic, experienced, wise, thoughtful ...
 
 

Do you know why you have these big veins in your neck?  They are there to pump gobs of blood into your brain.  Why?  Well certainly not for any evolutionary advantage, since one good bear claw swipe to the neck and you are quickly a gushing history.  The reason mammals risk that design vulnerability is that the brain requires a lot of "food" which your blood flow supplies.  In fact about 20% of your total daily caloric burn occurs in your brain.... and the more you think, the more calories it uses.  So trying to figure out Sonar's constant changes is actually good for you -- you are using your brain for the purpose it was designed for, resetting the wiring, building new pathways, burning a few more calories, getting brain fit and staving off Alzheimers.  Now if you stay with 8.5, your brain will slowly turn to jelly and you will begin to drool.  That drool will drip into your keyboard, shorting it out, blow up your motherboard, start a fire, and burn your studio down along with the whorehouse next door.  Is that what you want?  A bunch of angry homeless whores kicking the crap out of you all because of Sonar change-avoidance?

Good post, Greg.    At least where I live, where there are too many bears, they are too short to claw the neck of a reasonably tall human.  They are more likely to disembowel you ... but in statistical terms, that is still down way way below most other forms of death, including such oddities as too many bee-stings, falling and hitting your head on a stone, chainsawing both your legs at the same time; while the standard automobile accident, disease, suicide, lightning, and electrocution are far above even the bee stings.     But I'm enjoying the notion of death-by-drool ... waiting for the statistics.

MGC59
My cat walked across my keyboard in the middle of a mixing session. 

This is totally why everyone should just have dogs - Cats are evil.

Anderton
 
 Seriously, though, I do find it much easier to assimilate monthly bite-sized pieces than a yearly banquet. When rolling updates were first discussed I theorized that would be the case, but it's turned out to be true. I feel quite confident that I know how to use everything that appeared in 2015.

Yes, the bite sized updates this made actually implementing the new updates in your music a LOT easier than the jump (mostly unlearning muscle memory) from 8.5 to X.

Ibanez Laney

MGC59
My cat walked across my keyboard in the middle of a mixing session. 

This is totally why everyone should just have dogs - Cats are evil.

GregGraves
Do you know why you have these big veins in your neck?  They are there to pump gobs of blood into your brain.  Why?  Well certainly not for any evolutionary advantage, since one good bear claw swipe to the neck and you are quickly a gushing history.  The reason mammals risk that design vulnerability is that the brain requires a lot of "food" which your blood flow supplies.  In fact about 20% of your total daily caloric burn occurs in your brain.... and the more you think, the more calories it uses.  So trying to figure out Sonar's constant changes is actually good for you -- you are using your brain for the purpose it was designed for, resetting the wiring, building new pathways, burning a few more calories, getting brain fit and staving off Alzheimers.  Now if you stay with 8.5, your brain will slowly turn to jelly and you will begin to drool.  That drool will drip into your keyboard, shorting it out, blow up your motherboard, start a fire, and burn your studio down along with the whorehouse next door.  Is that what you want?  A bunch of angry homeless whores kicking the crap out of you all because of Sonar change-avoidance?

If you write a novel, I'll buy it 

Thanks again all for your thoughts.  Tonight my glass of wine (or something) hit my keyboard and my mix is now louder.  I always strive for solutions....  Maybe an option on selecting how shortcuts work?  Old, new, disabled:-)  Yes I know i can *manually* disable all so don't beat me up on that.
 
Q: How many guitarists does it take to screw in a light bulb?
A: As long as it's a leading edge, brand new optimized, never-heard-before light bulb.  One.

bapu

Ibanez Laney

MGC59
My cat walked across my keyboard in the middle of a mixing session. 

This is totally why everyone should just have dogs - Cats are evil.

 

Sadly, I must confess that my cat is my best friend. 
 
After many incidents of keyboard ambush, I've learned that screenset 1 is my second best friend. Sometimes he does things with a few steps (literally) that I can never understand or replicate.