I'm not a fan of the limited uses of Interject, especially after they seemed to make a big deal out of it. I hate to make a second comparison today but I guess I have to. In SWTOR, pretty much all the jobs had an interrupt ability with no diminishing returns and unless the enemy was specifically immune to being interrupted, you could interrupt EVERY ability that had a cast bar, didn't matter what it was.

If an enemy used a lot of cast bars, with the right combo of abilities you could completely lock them down and make them unable to do anything. It felt great coordinating that with your party and completely shutting down a dangerous enemy so it couldn't do anything. While I doubt the devs of this game would ever go that far, I'd love more spells to interrupt and have them made more dangerous if they aren't interrupted.