You missed the part about it being an 'exploit',didn't you?
I'm not saying they shouldn't fix it, I'm just saying in the greater scheme of things it wasn't causing any harm and there are other things that need fixing before that. The real question is now what happen when you disconnect or CTD? Because that's the "real" problem that mechanic was addressing.
As for it being an "exploit", it's not like you needed to do anything elaborate to use it. It was advertised by Bioware itself that you wouldn't lose your XP if you rejoined the same match, a lot of people have put 1 and 1 together...
Personally, I wouldn't categorize that as an "exploit". You don't get more XP, you don't get more gold, you don't clear the game faster, you don't skip any area, you don't get better items, you don't one hit kill everything, etc. In reality, it doesn't do anything a normal lost connection + rejoining of the same match would do.
On the other hand, animation cancelling does boost your damage incredibly, it gives you more mobility and survivability, it does change the game a lot. But then again why would I complain, it's not like it negatively impact my games if someone uses this...
So sure, call it an exploit if you want to, but it was far from having a negative impact on anyone... If you wanna be a purist, people that ran with the pizza on ME3MP were all cheaters for using an "exploit". There's a reason Bioware's devs said it was a clever use of the mechanics...