I see loads of wedges that are very flat and I have never really understood why. A very flat wedge allows the machine you're wedging (lol) to either go straight over the top of you or simply slide off. Plus, the flatter the wedge the further onto it another robot sits, putting the weight of the other robot over your wheels. ANOTHER thing; a low wedge when used to ram another robot into something solid (arena wall) allows the other robot to just fly off backwards whilst your machine takes the brunt of the impact.

As long as it's not 90 degrees to the floor I think a steep wedge is better. You can keep the other robot in front of you (easier to push 'em around, specifically into the pit), you ram them into the wall not you, etc.

I just babbled for 30 seconds there... take from it what you will.