IMO the predictability or the "the offense was figured out" complaint came down to two issues.
1. The loss of Williams made both our run blocking and pass blocking much, much worse. Eich wasn't as good at making the calls, anticipating stunts, etc. He couldn't reach the second level to run block like Williams could. And he made a few too many critical mistakes in pass pro.
2. Good teams figured out they could align in a pass favorable front, but double Hill and Waddle (when they were both in). Miami would then option to pass and our third receiving option couldn't separate.
Brewer staying healthy would solve the first issue. He is arguably a better run blocker than Williams was. In pass pro, he isn't as stout one on one heads up against the NT, but Miami Cs are rarely asked to do that. In help situations and at making the calls Brewer is comparable to Williams. My concern is if Brewer doesn't stay healthy. We need one of the UDFAs to upgrade that back-up spot or there are reports that Williams is expected to recover and be re-signed. Although that isn't expected by the start of the season, more like October if it happens.
The second issue is what OBJ, Jonnu Smith and Malik Washington have the best chance of alleviating. I also think Achane and Wright could factor in. I see all four new additions and Achane just through development as being upgrades over our third receiving options last season. It's tough to learn the receiver position in this system. There are sight adjustments that only work if the QB and th receiver are seeing/reading things the same way. It takes time for that coordination to develop. Fortunately OBJ was in a very similar system in LA, so that learning period should be shorter for him. Achane being in year 2 should also help him.
Another thing that would help the second issue is just saying "f*ck it" and running into unfavorable box looks at times. You can't let the defense dictate what you're going to do all the time. Sometimes you just have to impose your will. SF often does that and IMO it makes their offense less predicatable.
I don't think that's necessarily a "play calling" thing for McD. Tua has the option at the line. I think he can be a little too aggressive. Both in terms of not taking the check down, but also in terms of looking for the potentially bigger pass play vs. just handing it off (wanting the ball in his hands, etc.). McD could help though by helping Tua be a little less robotic in those line reads. It's that next level of playing QB where you realize that you're guy is just eating a DE or DT's lunch and you keep exploiting it. Miami has done that against DBs at times in the pass game, but I don't recall them doing that in the run game.