The assumptions: First, assuming that most robots have some form of functional shooter. Second, assuming most robots may have trouble with intakes or shooters from time to time, with some types needing more help than others. Third, assuming that 66% or more of the time this robot will be playing defense; the remaining 33% will be taking defensive hits. Fourth, assume that a reliable automode--or adaptability to partners' automode(s)--is important.
To seed high: Score one ball in auto, high or low. Reliably inbound the ball and immediately dump it to a partner that can shoot accurately. Play shutdown defense. Wash, rinse, repeat. In absence of said accurate partner, dump to someone that can drop in the low goal quickly, and revert to defense.
MCC: Robot with a strong drivetrain, a quick-acting acquisition device, and a reasonable target for inbounding. For a slightly more advanced MCC, add a shooter capable of making it into the high goal. (I would not necessarily rate a shooter as a requirement--the assists are more important--but if you run into a pair of BLT robots on your alliance, it's nice to get 10 points as opposed to one as your base.)
I actually have a robot in mind for MCC, believe it or not. And it's a rookie team that's been in FTC for a few years now, with a couple of members off of the team I currently mentor.
FRC5124 sported a 2-wheel-over-fork pickup device that could function as an output, an accurate 1-ball automode, and a shooter with enough power and accuracy to score... but dat surgical tubing do. They also played killer defense. Take off the shooter and you've got a low-goal assist specialist.