I use the default UI as well. I don't run out of buttons because of InnerSpace and it's own internal macros/keymaps. Nothing has to be bound in game..and if it is bound in game it's overridden...so I have about half of my abilities that are keymapped on 2 bars [the ones which I need to see cooldowns mostly] and I just remember the rest of my buttons. I also do not use /castsequence or /castrandom macros...everything, that I think is useful, is bound to it's own binding.