If I read Infinite Worlds correctly, the area of effect is always a 10' radius. However, the Shaped Infinities Paradigm says you can exclude up to one 5 foot square per witchwarper level from the effects area. So, as you get to be a high enough level, you can exclude all of the squares, which seems odd. Am I missing something about the area of effect of Infinite Worlds?
You're not, the ability is overkill after a handful of levels (and immediately when you qualify for it). If there's ever some way to expand Infinite Worlds those extra squares might come in useful, though.