PvP/PvT/TvT map pool could have - maps with crazy thirds of differing distances, really wide-open naturals (such as Dual Sight, a pretty decent map when zerg isn't involved), mains with weird entrances.. all sorts of awesome, creative layouts that just aren't possible because of the existence of zerg.
ZvX/RvX would have - maps with more standardized nats and 3rds, such as what we have now.
I know what you're thinking - the reason these problems exist is because of the core design of the game, which is quite flawed (such as Protoss' over-reliance on FFs). Well guess what, Blizz has already made it clear that they aren't going to change SC2 -that- fundamentally for HOTS. So this is a possible plan B.
Yes, with HOTS the maps will get a little more interesting due to P's slight better defense with MSC, and little fun things like collapsible rocks (and health ponds, it looks like). But we will still be held back soo much from where we could be.
(I don't think Blizz will ever do something like this for ladder, because it would be tantamount to the balance team admitting defeat, but that doesn't mean tournaments couldn't do it.)