Of course you are a top coach, manager, and tactician, you see Wilder everyday and the trading at the academy. It isn’t the system that isn’t working it’s a mix of bad luck, bad injuries, and of course severe lack of confidence, and bad play and bad decisions. Back the team you mug and stop pretending this is FIFA.
We lost the last 3 last season and first 2 of this with JOC (except at Southampton) McB and Henderson available/in the side, so that's why, regardless of which players we can or can't select, I think the way we play 5-3-2 isn't working any more.
I do agree with much of what you say though.
1. The injuries will have had a major impact on the results this season. JOC, although he played in 4 of the 5 losses I mentioned, has been a huge miss, With him continuing in the side, I reckon we would have pulled it round to be in a better position than we are, although nowhere near last season's levels.
2. Chuck in the bad luck you mentioned, including Egan's unjust red card at Villa, Leeds late winner off of Bamford's nose to name just 2, coupled with JOC's injury, and the already-fragile confidence began to drain even further.
3. The bad play and bad decisions you mention will bring any system to its knees.
This is the biggy for me though. I think (with my admittedly severely-limited top coach, manager and tactician ability!) that the other teams/managers have worked out how to deal with our system to nullify most of our forward play.
The OP then with this in mind, was more about how we can change effectively with the limitations of our players (when all fit) against better, more aware players.
Even with everyone available, I don't think we have been (would have been) able to operate as effectively as the first few months after promotion when a mixture of surprise and confident players got us the 1 goal wins (plus the brilliant 3 goal performances against Burnley, Spurs and Chelsea at home) where back end of last season and almost all of this, they haven't.
For what it's worth, even though teams do now know what to expect from us and how to counter it, I do think our system could still work really well, but we'd need an upgrade on almost all the players which isn't going to happen, hence me asking what formation might be a better option for us now.