[EricH]

Non-flat surfaces, in a fairly large proportion.

Back in the days between 1999 and 2004, there was some form of structure to climb on every year (save 2002). These structures could easily block midfield, which many of them did, or make staying off of them and staying competitive very tricky. Since 2004, we have not really had that midfield barrier. Sure, we've had to go around triangles (2005), go up ramps at the end of the field (2006), and dodge large structures (2007), but none of them have had that same "I'm in your way, climb on/over me" feel that those older ones had.

A number of prototypes that are out there seem to assume a fairly flat floor with primarily carpet covering. But let's not forget, the GDC has been known to use as many as three different surfaces in one game, notably in 2003's ramp and 2006's ramps.

I don't think the CIMs will entirely disappear. However, let's see what happens when we can only use the BIG CIM's from the 2006-2007 era. More weight, less power, and how on earth do you get the pulley and tensioner off this darn motor without breaking it? That's going to be a sight to see... (And yes, that would be a dirty trick. The only things in the KOP's those years that weighed more than the big CIM were the compressor and the batteries.)