Id be happy with a square connector for negative and round for positive so that I dont have to watch my buddy fry another esc. or have 1 male and female on a battery so you cant mix it up. its all simple stuff that could have been done along time ago.

Here are more ideas.

the voltages are going to have to get higher. you cant even get a decent vacuum under 24 volts now. this makes your connectors smaller.

I think you can make connectors smaller if the contact area had more surface area. for example a copper screw.

Ive been working on magnetic charge leads. polarized so you can hook them up backwards. 30 amps requires allot of surface area.