It wasn't an issue at all.
It also wasn't gimmick plays, it was just QB sneaks. Jacoby Brissett is bigger, so you put him for sneaks. It does two things, 1) saves Tua from the punishment and 2) it sets up the fake sneak sometime later in the season, where Brissett can drop a dime to wide open Waddle for 6.
QBs are not made by QB sneaks so its not hurting his development at all.
The only thing that got weird was the delay penalty after the sneak, but all they were trying to do was draw NE offsides, thinking they might get squirrely since Brissett was in all of a sudden. But it was worth it, IMO, as both sneaks got the firsts.
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For the record, Tua played waaaaay better than J Allen did against Belichick last year and had very similar stats to what Mahomes did against Belichick last year as well.
I just think its tough to play in Foxboro.