Hi BB, looks the good basis of a team and, as you say, midfield is a bit weak.
Like you it seems, I have no compunction going 4xFB... as long as I don't have to do many restings(*). If Enrique does go to Liverpool, you get three such clashes in September. Plus it's tough pickings in that FB area again this year and I've not come across any effective combo of 4xFB's yet. Still looking however.
I wouldn't go Collins
and Warnock. At those prices, one of them is worth a gamble IMO but not both; McLeish is more defensive-minded and has just signed a good goalie but I still have my doubts. With Lescott, it's possible he'll keep his place when Toure is back if he's been playing well; also Joleon suddenly re-discovered his goal-scoring form at the end of last season. His one against Bolton was one of my favourite goals of the season.
In your midfield, Moses is not a bad shout, if you're one to go on pre-season form and think he'll step up in CNZ's absence. He should provide the odd goal but will there be anyone there to convert his assists? Sinclair should be OK but I don't think he's going to be a standout scorer like, say, Adam was last year; scoring three in the play-offs was a bit misleading as his stats were good but not very good, last year.
The other two I worry about more. Sessegnon is I think a bad pick; he won't be played up front again except in another injury emergency and he's not guaranteed a starting slot IMO. Wilshere - what role will he play in the Arsenal midfield? If Fabregas and Nasri both go, he might be worth a pop but right now, I'd stay clear to be honest.
Possible replacements will be tough to pick as midfield is over-priced this year. In my main team, I've gone for RVP plus a Tescos Own Brand (note: not Tescos Value) striker to free up money to boost the midfield options to 4.xers pretty much all round. If you don't want to do that and are stuck on RVP+Rooney, then you could pick a few dull under-performers (e.g. Blackburn midfield) to get you going and swap to the bargains when they emerge.
(*) copyright the guy from Internet Service Providings on FoneJacker