We ended up beating the raid the other night. Callus was an odd fight that seemed to have either a bug or an intentional limiter in it. During that fight when you get on the platforms to kill him, we'd get him down to about half on the third platform, and the game refused to let us use the fourth one. (It just started the next add phase.) However, during the second damage phase, we got to use it.
Power ammo always drops from yellow mobs just FYI. If you are low, kill them.
Other than that I always try to give very specific instructions for people. As detailed as possible so there are no surprises.
I did have some problems refilling my power ammo to full at times, but the issue was usually with other types of ammo. In most situations, you don't normally swap to energy weapons unless there's a shield or for some reason, that weapon just works better due to some weird circumstance. For example, once their power ammo was spent, some raid members used Coldheart on Callus (I think?) because it deals more damage over time. So, what ended up happening is that I'd use my Kinetic weapon almost 95% of the time on most fights, because I had no reason to swap, and that meant that I usually ran really low. If I do get ammo to drop, it may not be in a great spot, and going to grab it could put me out of range of a raid objective that I need to take care of.
I guess it bugs me, because apart from limiting power weapon usage, having limited ammo in this game doesn't feel like a necessary aspect. In a game like Resident Evil, they limit ammo because (a) it's a horror game, and (b) you're not meant to use your weapon all the time. The only thing that I could think of is that Bungie expects you to go around meleeing more often...? I melee in a few spots like when the dogs release during the Callus fight.
What if they just added an ammo restoration device somewhere around boss fights, and it cost glimmer to use it? I'm already maxed out on glimmer, so it would at least give me something to spend it on. That wouldn't fix the issue of poor ammo drops, but it would at least remove the need for ammo runs while also giving them a "gold sink".
That's funny, I did my first raid this weekend (first raid ever, in any game) and had the exact same experience. It took us almost four hours to finish the raid, we did beat it but 1.5 hours were spent on that section where you stand on the plates in large part because I thought I had to stand on that circle the whole time.
We eventually swapped to the rotation method instead of the static method. I'm not sure if I can say which method was easier, but I didn't have to deal with the psion at all, so it might have been easier on me.
The raid did take us nearly 10-12 hours though, so it definitely wasn't a quick affair like yours. Albeit, it doesn't help that we started rather late on both days (around a 1-2 AM start time).
I played a hunter and I had a bad build with too much mobility and little recovery. Recovery in the raid seems like the uber stat, well... not just in the raid but the game in general Recovery seems OP, but in the raid you frequently have to take cover and that's where getting back in the fight sooner is everything.
I'm wondering if mobility would be better on the last part of the Gauntlet fight? One thing I noticed is that I got left behind rather badly during that part, and I was sprinting the entire time. Albeit, I did get screwed over a bit during one of the jumps as it made me climb up to the top hole when I was trying to jump into the middle one.