If Allen hadn't been such a non-factor so far, I would have expected a lot of 2 tight-end formations with a bigger back. No need to play the Falcons' game when the Pats could just pound them...it would have been the best way to neutralize their speed. If the Falcons want to keep their faster, lighter defense on the field, then let have them tackle Gillislee, Gronk and Allen. If they substitute to get more bulk on defense, let them cover Gronk and Allen with slower LBs.
Plus, that game plan would have been very different than the Super Bowl, and thus an additional adjustment for the Falcons to process.
Now, with Allen having played so little lately, I'm not expecting that game plan to actually occur...