As ever, it's all about opinions, but these would be my top three factors, although you could argue they are actually 5 or 6...
1. O'Connell injury - a massive blow to us, not only from a defensive perspective but he's been integral to how that left hand side operated with Stevens and Fleck in driving us forward. People talk about our 'over lapping CB's' being nullified but for me losing O'Connell meant we were always going to struggle to keep doing it well. Now we can't seem to do it at all and it's also inbalanced the side. I've read we should have replaced him and I'd like to ask "Who with?" - he's been fairly unique as an attacking left footed/left sided CB. I can't think of anyone who would be an ideal replacement without spending about £40m.
2. Injuries and Form - 2 reasons really but I think they affect each other. Last season the back 5 and pretty much the midfield picked itself for the majority of last season. We were lucky to have a run where not many players, and certainly not key players, were getting injured. This season, it's been horrific. I think this is directly linked to the poor form of players. Fleck in particular but also Norwood's (although he hasn't been injured as far as I know) form has deserted them. I wonder how much Fleck's is linked to the loss of O'Connell, however Norwood has just been inexplicably poor.
3. Recruitment - it pains me to say it but I think we've made several BIG mistakes. Firstly Berge, I'm so disappointed this hasn't worked out. You can see there's a quality player in there, but he just needs to stamp his authority on the game. Sadly, I don't think that's going to happen with us and I can see him moving abroad in the summer. Brewster - this one baffles me a bit. Clearly he's got potential but we needed somebody who was going to score goals for us this season, not next season in the Champ. When we were in League 1, we let DCL go even though he had great potential because we needed to free up some cash to get players that would get us out of that League. I get that and fully agree with the reasons. We couldn't afford to spend so much money on players that are 'ones for the future'. We needed players that were going to secure our prem status this season. No idea what the clubs position is on fees and wages et al but for me we should have been in for players like Callum Wilson or at least some with Prem experience. The drop off from Henderson to Ramsdale is plain to see but I'm not sure how much Wilder could be blamed for that. Perhaps there were better options but it seemed a decent signing at the time.
I also think our 'style' or rather lack of it has been a big factor. Our players are too tempted to hoof it up to McBurnie and that's not how we play, furthermore we're not very good at it. Not McBurnie's fault but I also see this as contributing to the lack of form of some players who aren't seeing the ball enough. Add to this rock bottom belief and confidence and it's quite depressing.