>>273287674
Never played Wipeout. Depends on the map. On some it's more the former, on some it's more the latter. I find that you can generally get by on most maps (that I've played anyway) without memorization, but you will absolutely do much better with a bit of memorization. 
>>273287792
I mean, I think I disagree with that a bit. There's rarely any big damage that comes to you when you smash into walls. All that happens most of the time is that you get slowed down a bit by touching the walls. And it's actually part of doing well. On a lot of maps, you want to touch the walls to get the best time, or rather, you want to not break. 
So I would say the game is very forgiving, but the skill gap can be large.