That's a decision only you can decide. Personally I think a main drain is beneficial. Of course everything has pros and cons.
If you are pulling from the deep end and from the skimmers you are going to have less "dead spots". (in my head at least)
If you ever need/want to drain the pool, that's much easier to do with a main drain. (no rental equipment needed)
My Suggestion is to ask the PB every question you come up with. This at least lets him know you are watching, and you aren't a complete moron. I bug the heck out of my PB with every question I come up with. He doesn't mind it, and it lets him know that I am anal retentive. So if he's not sure what we want, he asks for clarification instead of just jumping in head first.
Apparently most homeowners don't ask many questions, they just go with the flow and only care about what color the tile is.