[GeeTwo]

I think most of the replies are overthinking the situation. "Change is Coming" is also reflected in the history - each clip showed some change taking place, and this year will be no exception.
Not trying to be a pisher, but given that the venues are already selected, we can pretty much count on the following assumptions being preserved:
Game played on a surface which can be laid over a concrete floor -- not a "water game" (or a "space game" or an "air game", for that matter) -- my personal favorite concept of launching rockets to harvest comets to deliver water to a moon colony is right out!
Field size not too much larger (certainly no larger than a basketball court)

We know up front that the control system will change (roboRio vs cRio, new PDB, pneumatic board, and so forth), but the game hint says that ain't all:
Rules we have come to accept as canon but which we can probably figure that at least one will change:
robot size (changed from 120" to 112" frame perimeter just 2 years ago, di'n't it?)
2 alliances of 3 teams
weight limit
bumper rules
carpet as a surface
And finally, the rule I hope they really are keeping: "if it ain't forbidden, it's allowed"

The bottom line is that SOMETHING changes every year, and this year is no different. This isn't a clue as much as a reminder (or perhaps a warning)!

My personal take on the real clues so far (large lightweight and long units in the KOP) is some sort of game in which the opposing alliance(s) robots (or trailers towed by those robots) are targets of a peculiar attack involving 60" long arms. 'Taint worth much, but that's my take so far.'

GeeTwo