AVALANCHE at the start of the game, specifically Barret, is much worse than the Turks in my opinion. The Turks only do certain things because it's their job, not because they want to do it. AVALANCHE chooses to commit terrorism, fully aware that their actions lead to the deaths of innocent people.
No, AVALANCHE didn't set out with the goal of killing people, Legend. The blast was larger than they expected, as Jessie points out. It's possible they might have only intended to take out the reactor but nothing else, something much more limited in scope and without casualties, but it ended up being more damaging than they intended. You don't need to ignore basic facts just to glorify your favorite characters and dump on everyone else. Oh, and AVALANCHE set out to atone for their actions long before the Turks ever even thought to. They were even willing to (and in some cases did) die to make up for their mistakes. The Turks have never faced nor sought out any consequences for dropping the plate.
And as far as the trio in the remake and how they've been practically ignored outside the trailers, it just concerns me because I don't know if that's a reflection of what'll happen in the game, if SE's pulling a bait-and-switch on us by showing us all this stuff about them in the trailers but in the actual game there's hardly any time or interaction with any of them and what was in the trailers was just about all there is. I'm hoping that's not true, but them not getting much attention outside the trailers doesn't help ease those concerns much. SE specifically said they wanted to explore and develop them, but outside the trailers, it's almost as though they don't exist. I just think SE's promotional efforts should reflect their stated words, is all.
And also, I'm hoping that, unlike in the original, the AVALANCHE trio won't be forgotten after they're gone and it won't be as if they never existed. I don't want to have to wait until Cosmo Canyon, possibly Part 3, before they're ever even mentioned again. There could be ways for them to naturally come up in conversation, flashbacks in Part 2 and beyond to allow them a limited presence in those games. Maybe even a sidequest involving making a memorial for them sometime in Part 1 after the plate collapse. In the original game, it was basically just one scene in the aftermath of the collapse and then they were almost never mentioned again. But grief and loss don't work like that, and they don't just disappear. We should be able to see Cloud, Tifa, and Barret struggling with it and trying to deal with it, each in their own way.