Ya, I had the same problem! Just bought new Diadora shoes to FIX THE NUMBNESS PROBLEM I was having because of wearing plain old sneaks with my toe clips! (besides wanting more power)...
I loosened the front velcro strap A LOT and loosened the rear ratchet strap a little bit to get through the first ride on the shoes. Then I moved my cleats back towards the middle of my foot (had started out with them closer to the toes) and it helped HEAPS.
Also a word about my Diadoras: I was worried when I bought them that they were a bit loosey-goosey on my feet, but I'm glad they are, since my foot spreads out a lot when I'm on the bike...