A few random ideas:
3. Maybe he is too tired due to Setien's training and his finishing is suffering
Yes, which is why people wanted EV out. Because his training sessions and match preparation were for old men. And our competition is not made of old men, but of very fit athletes.
Your bad logic is astonishing. You're trying to imply that if veterans can no longer train properly, we should hire puppet managers who should lower the bar so these veterans can half ass it until they are 36. Maybe just train 1 day per week at most.
Dude, the level keeps being high. Very demanding. It's how veterans sense it's time to retire and pass the torch. Our veterans have been pampered to the point the whole team's intensity has been brought down to suit them and their comfort. Which is idiotic for any professional team. It's why we always are bullied and overpowered in terms of agility and speed. To even imply this when you claim you value physicality and speed and energy is mind-boggling. You really don't realize how bad your arguments are?
4. Maybe he is moving more during matches so he is tired once when he gets into finishing chances
Which is why trainings are important. If most 32-33 year old players can do it, so should Messi. If he can't and is hurting the team -> retirement. This team should no longer tailor its match preparation and fitness programs based on how much 32-33 year old players are willing to run.
5. Maybe our attacking patterns and movement is different than under EV, so Messi is shooting from different positions
This is true. He now shoots with less accuracy from 7 yards in 1 vs 1 with the keeper, than from 25-30m free-kicks under Valverde. He needs to improve, as the only responsible for this bad finishing is Messi. But imo this is tied with his discomfort issues, so he has an excuse imo.
6. Maybe Messi has confidence issues under a new coach
If he has confidence issues with a manager whose tactics give him more and clearer chances to score, he needs to get over them.
7. Maybe there is no no9 in a team, so the opponents are marking Messi more heavily so his shots are weaker due to having too many players around him too often so he has to shoot from bad positions
True with the first part. Horribly false with the 2nd. He shoots from better positions now. It's just that the finishing is way off. For example, the lob he failed to score vs Getafe was piss easy for him. The chance he missed vs Bilbao, again, piss easy for someone like Messi. These are not bad positions. These are perfect 1 vs 1 positions that he has wasted.
So, my friend BBZ, every point where you still defend EV and attack Setien is plagued by insanely bad logic. Every other point where you don't do that and don't desperately look for an agenda, you are right.