You might be right, but personally I think the issue is personnel, not the system. We have three fit central midfielders (none of which have any pace), one fit striker, two right wingers but no left winger, one fit right back with no pace who struggles to last 90 minutes. We have a bench of kids and inexperienced seniors. Whatever system we play right now there will be some square pegs in round holes, but as it is our two main issues are not tactics but our inability to defend set-pieces and to finish the chances we're creating. Personally I don't see how either of those things change by switching to a different formation, but maybe I'm missing something?
From OG's perspective I totally agree with you and others that he might be concerned about his ability to get the players he would need at United to succeed, but you would think that would be discussed were he to be interviewed. As sh!t as it is for us, an ambitious manager doesn't turn down United, so then it might come down to whether Palace would release him and what compensation they would want.