Finished my Insanity run. Sentinel works very well for this difficulty. Most notably, because of the shield overload function.
Time it well, and it is invaluable when running husk or collector gauntlets. That, plus always wearing the melee-enhancing armor. Literally punch a hole in the wall of husks, allow the shield break to act as a minor smart bomb, get clear and prep again for when the crush of undead fans tries to get their hands on you again.
Regarding the end run, despite apparently doing everything right, Grunt, Jack, and most infuriating of all Tali got killed. Tali was the engineer/door choice, Jack/Legion/I dominating enemies to keep her from roasting...and she still gets shot in the end. I don't think my jaw has ever dropped so sincerely at anything in a videogame before. Very angry...and then Jack gets taken away...!
Anyway, went back to a previous unfinished game as Engineer, Hardcore difficulty. After playing Insanity, I had to check if I had it on Normal.
ME2 has obviously earned a spot as one of my all-time favorites. Setting aside for now, but still itching to play more after the 4th of July weekend.