The U in 7-man does not have LOS responsibility like in 5-man so there is less of a need to get to the LOS. I usually move up to avoid the crossing routes. That doesn't mean the wideouts won't still avoid me, but moving makes it a little more difficult. Being aware is key to avoid getting knocked over.
I did see an 8-man all-star game where the U stayed 8-10 yards deep on each play regardless of run-pass. That's a possibility for future mechanics since the C will be responsible for spotting the ball. It looked odd, but these things evolve.