For me, the biggest challenge is to find the 'right' buddy's for photography diving. But if i really want to focus on taking photos, and it takes out 10 minutes or so until that shy fish comes out, and 'poses' properly, it's hard to find buddy's that don't mind the waiting. That's when possible, i preferably dive alone...
Or at least, away from the group. The only thing they do (most of the time) is make a lot of noise, stir up the sand, and when i just want to take the shot of that turtle, swim in front of my lens, and upon that, scare the turtle away
But hey, i'm a social guy 
Do you really have to wait such a long time until your gear recycles? i have a canon 450d with a ds160 strobe, and the longuest i have to wait is aprox 1 second. Or are you talking about high speed action pictures?
And indeed have the right lens on the camera. The guy that invents a really good one-in-all (1:1 marco, or even more + wideangle,...) will be a millionaire...
Jochen