Cohen le Barbare wrote...
I used to skip pull on my drells and focused on grenades, but now with the new gear, everybody is gunning for ammo boxes. I now spec pull for bioexplosion and with reave at 6, it's actually a good tradoff for my playstyle. I can detonate on my own, and my teamates can detonate two of my powers. Oh, and I love the bioexplosion sound 
This. I am wondering why so many people leave it out. It varies in my builds for the justicar, but I usually spec it to 3, but more often to 4 (area). I get great results with it (and yes, this is on gold). Especially if you don't have another biotic with you to detonate for you, it is a superb way of wrecking up groups. Reave (staggers) -> headshots to get shield out of the way -> pull -> reave for explosion.
Basically, by the time a group gets to you, they are devastated. Not to mention the minor troops (husks, cannibals, assault troopers, geth troopers) can just be picked out and be used to do damage with explosions to any shielded/armor enemy in the vicinity. Hell I even pulled phantoms and exploded them, you have to be quick and smart about that though, they use their rocket clothing to get back to the ground, plus the power does not work when they are in block stance. I have defeated quite a number of phantoms by reave -> letting them approach while you are firing at them, then bubble for an explosion -> immediately use pull -> reave.
It's only useless against anything with armor, but combined with reave & the bubble it makes your diversity a lot greater, imo. But this of course also comes down to your own playstyle and preference. But I don't find the power useless at all.
Now for things I don't often use, carnage & blade armor stand out the most. For the rest I tend to vary my builds after promoting, never really stick to one build.