At this point, there is nothing Miami can do to fix the reasons for their losses. Of course, it's obvious that they lose without Tua, but hopefully for next year they make enough changes so that they can still win if Tua doesn't play and be even better when he does play. IMO, this is what they need to do...
Special Teams: Get a better Kicker and a good return man. Field position is important; I miss seeing Hollins downing punts near the goal line every other game! (Although, I guess it's good if they don't have to punt at all.)
Offense: Keep improving the o-line and back-ups. The speed of the WRs and Tua's quick release make them look better than they really are, and they're nowhere near as good when Armstead is out. They need a line that can provide a back-up QB with a little more time, and maybe get a real power back.
Defense: Fix whatever is causing them to be embarrassed by mobile QBs, whether it's by replacing guys who can't tackle, or improving the defensive gameplanning and scheming. Also, they allow too many guys to be wide open coming off the line or in the middle of the field. Guys returning from injury will help a bit, but maybe they need a better DC and a new defense.
IOW, they need to build a team that has an above average defense, and an offense that can be dominant with Tua, yet still be able to win with an average QB. I know it's tough to build a contender over one off-season. This year we see that the offense can be special (just need a little more upgrading on the o-line), so for next year I hope they can transform the defense into a top unit.