I think there is already enough incentive to use sensors.
This year we didn't have time to setup our shooter speed control on the robot until half way through our first district; the change in firing rate alone was jaw dropping (going from a 1 sec delay between shots to allow the wheel to spin up, to a .4 sec delay), add in the additional reliability (since an open loop would overshoot if left running too long, or undershoot if fired too quickly) and you can make a really strong case that sensors are an important part of the game.
Before I joined our team as a programming mentor, the team was heavily mechanically oriented, and they didn't use many sensors. Last year, I took my first swing with an encoder on our roller wheels (short range vertical shots), but not until we reached Michigan State Champs; this year we built a US1881 Latching Hall Effect sensor and a couple ring magnets for speed sensing, along with a gyro to keep us driving straight. We've also toyed around with PID controls and such, but haven't gotten enough expertise to use them effectively.
I think it is good that the games remain accessible to teams that don't have strong programming and controls abilities; however building your capabilities (in-season or off-season) has some pretty huge benefits in competition, but also in learning opportunities.
We're very lucky to have Mr. Ether nearby to bail us out when I get in over my head, and to dangle carrots out there for me to chase
