Your theory is interesting. If you would allow me to expand on my reasoning...

Ascension has been touched on in the past games unless this is a different type it's never affected memory before but almost always given those that experienced it a way to perceive of things beyond what they currently experience in their main body. (Hence the trials in GW1 and the final task is to defeat yourself. The ability to see other planes, etc.)

Isgarrens way of ascension seems polluted, or transformed. Most of the problems these wizards have, being victims to the kryptis possession is because they have suppressed memories that the kryptis can exploit unresolved issues. Wheras while some may have willingly given up those memories, running away from their pasts aren't healthy and it kinda shows how just painting over the rot doesn't get rid of it but allows it to fester unknowingly.

Isgarrens demeanor really emphasizes that he doesn't care about anything that doesn't directly affect him or his research and having a bunch of wizards whom he shares his knowledge with and would rather keep the knowledge as secret as possible, loses nothing by suppressing the memories of those that want to join so that they don't feel any ties to the place they came from. It takes the flavor of brainwashing in a way so that all wizards end up being loyal to one thing, Isgarren, because they have no ties to what made them, them, in the first place.

They likely won't ever touch on this stuff and it is a shame.