I had a pair of emerica nailer's a while back, one of the best shoes I've ever skated. but you see that stupid looking ankle cuff? that's three lips too many, and made it the most annoying shoes to put on and take off. take that shit off and it's all gravy.
to cut off proper, buy yourself a blowtorch to use and follow the natural lines of the shoe - the heat will cauterize where you're cutting and ensure a perfect finish.
also:
and if you only want to do this because you think the shoes LOOK weird then thats just lame.