I do agree that Ichigo needs more techniques but that probably won't happen for a while.
As for Hitsugaya, his Zanpaktou is more of a Kido/elemental type which explains his diverse movepool. Yama-ji has a lot of moves as well as Kyoraku and Ukitake. They all control certain elements so more moves come naturally to them.
Plus they have the advantage of training their techniques over the years they have been captain.