A: We chose to go with the subscription-based model instead of that approach. We've taken the approach that we want players to feel like it's a level playing field once they're in WoW. Outside resources don't play into it -- no gold buying, etc. We take a hard line stance against it. What you get out of microtransactions is kind of the same thing and I think our player base would feel betrayed by it. I think that's something else you have to decide on up-front instead of implementing later.
Usually it's best to avoid a lot of instance runs. It is too difficult to account for bad groups, and some instances are too far away with too few quests. Since the experience is very good, it's a good idea to clear nearby instances which have a lot of quests once (Gnomeregan, Deadmines for Alliance). Distant instances with few quests should be avoided (Deadmines for Horde). Low level instances can be cleared by paying or befriending a single high level character. However, since patch 3.3 a new Dungeon group finding system has been implemented, as well as a direct port to dungeons (when entering the group you get ported to the dungeon and back to the same location if you leave it) and thus the travel time to dungeons has been greatly reduced. This makes it a good idea to complete quests or grind while you wait for a group to become available.