Brutes are NOT flimsier than Scrappers. But Brutes are not in a very good place right now. Tankers keep getting buffed, and that is the go-to armored AT.
Sentinels got a nice rework. They are decent. They were in a horrid spot. they are now.... There are meh. Especially after 50.
These are my opinions. I have Tanked Recluse in MoMLTF twice successfully on a Dark Dark Brute. But that does not make it in a good place. That just means I did to the Brute what NASCAR does to a chevy. And people have played that build (at least one person) and swore they died all the time. I never think I am that good a player. Maybe they were that bad? I have run tons of Sentinels. DPS with a gimmick. and meh DPS.
I am currently fixated on Corruptors. But I do not like to heal or buff. I like to Corrupt. So I run Dark and Ice. Dark has great heals but it is centered on me and applies a -regen. debuff. Corrupt. Corruptors are the only "S" class AT in CoH. Every Corruptor, regardless of powersets, is an "S" class pick for a team. My opinion. Depending on Powersets, AT, and opinions most non Corr toons are A to C. Less kind players immediately assign Ds and Fs to certain powersets and/or ATs. Is it fair? Is it right?
Do not look to "balance" the game through change. You will have a interesting fight.