[anishde]

Accidentally voted for the wrong option :/

But when it does come down to it, honestly? Going under the low bar is definitely worth it. Copying off Rebound Rumble is not the way to go here, because should a robot this year have a significant amount of height, there's a good shot at it tipping (therefore failing at the majority of other defenses). Just going off the top of my head, it would take a seriously good driver to get a tall robot up over the Cheval de Frise, the Rough Terrain, the Ramparts, and the Rock Wall (for much the same reason why you never saw the "standard shooter" from 2012 crossing over the central bar across the Rebound Rumble field). The only defenses where I see a serious advantage coming in with a taller design are the Portcullis, Sally Port, and Drawbridge, and that's something to consider.
Traffic has been a primary concern of many teams in regards to the low bar. However, based on the limited number of designs that have been made publicly available by teams, with the right wheels, good balance, and good driving, doors open up (NPI) to many other defenses as well.
The fact of the matter is, don't be too quick to turn your nose up at either option.