Yeah, it's a shame we don't have experience docking/building things in orbit... oh wait, ISS. It's also a shame we don't have experience transferring fuel on orbit... Oh wait, ISS.
Fuel depots are not a difficult concept and the benefits far outweigh the deficits.
HLV's are just not cost effective at one every 2 years. I'd rather have a medium launcher with a much higher (and successful) flight rate.