My advice is to keep it simple. The two most important things it should do are:
- Carry the robot between pits and field, and back.
- Give you a safe and productive work surface.
Everything else is gravy.
Keep it small enough to fit in the pits and allow people to work around it. Locking wheels are helpful (but make sure all students know how to lock and unlock them). Swiveling wheels on one end and straight wheels on the other work best. And a handle at waist height for easy steering and pushing or pulling. Ropes are not so good, but better than nothing if you have a low-to-the-floor cart.
I've seen some teams with scissor lifts or pneumatic jacks. Sometimes I'm jealous, sometimes I'm glad we have a simple, solid, flat, dependable, safe surface.
Shelves and drawers are nice for carrying the operator console, bumpers or covers, some tools, spare battery, etc.
If you're using pneumatics and an offboard compressor, the cart is a good place to keep them (with a battery for the compreesor). Even if your compressor is onboard, you're allowed to pre-charge your tanks.
No matter what, it should be a fun project to work on, now that the pressure of build season if off.