I might be sounding like a broken record.

I still am failing to see where some believe that Solas possesses a "mind-altering" skill set. The ability to change or erase someone's memories. The evidence that we have, only seems to come from Cole. During our first conversations with Cole, he can tell the Inquisitor about how (and
why) he can make people forget.
Including himself. Now, if someone chooses to interpret Cole forgetting Solas' plans, as some sort of manipulation on Solas' part, that is entirely their choice. I don't personally see it that way, since Cole (once again, going off of those first dialogues with him) is pretty clear as to why he uses this ability of forgetting.
It is true, that there is one dubious point, that might influence the idea of Solas having the ability to "bend someone's mind" (for the lack of better term...sorry about that

). During the banter Cole and Solas have, when discussing Solas' past, Cole begins to reveal things as the memories come to him. Then he "gasps" and says, "Where did it go?" . Solas then apologizes to Cole, but explains that this is a hurt he can not heal. To me, all Solas is doing, is
blocking Cole off from those memories. One minute Cole has access, and the next....he does not.
The only evidence of altering or removing memories, is from Cole. You can even see him fret over it a bit, when he starts becoming more human (if you follow that path). Little things he used to do, without others knowing
or remembering (i.e. honey in Leliana's wine). It is a talent that can become harder or hampered when taking the human path, and it does illustrate (in a "meta" way), how often he most likely used it amongst many at Skyhold.
BTW, as much as I am squeamish about mind reading and memory altering (NO one wants to know what is in my head....or most peoples heads

), Cole being a spirit and having a very
specific purpose, does make him an exception for me. At least, in this story. That may not be true for other gamers, and I can appreciate that. But for me, I see his talent as unique to his very make-up and being. It fits his role, and I as both the player and PC (so far all of my PC's have been of a similar mind on this matter), are accepting of this.