As for cross class skills I'd say internal release (because it's good and easy to get) and provoke because it's one of the best tanking skills in the game and their isn't a level range where it won't be useful.

As for dungeon pace I'd say just pull one set of mobs at a time, mass pulling is for when you out gear content (levels 50 and 60) Just don't hang around between pulls and I'm sure everyone will be fine with your pace for the most part, anyone who isn't is probably being unreasonable anywasy. During leveling it's worth noting that AoE damage isn't really that much of a bonus until your DPS get their AoE rotations anyway. Fire 2 is good on BLM for example but it's not until they get Flare at level 50 that their AoE DPS is anything to shout about so pullling big early on is just stressing you and your healer and not really speeding anything up.