The thing with Everton is, they've massively over-achieved with Moyes in charge (saying this as an Everton fan), but despite that, they almost should be over-achieving by even more. It all averages out over time and we end up about where we deserve (the table never lies!) but you look at the contrasts between some performances, and know they could be playing better half the time. Wigan game at the weekend is a good starter.
I don't think we're likely to do much better than Moyes given the funds available, but equally, there's a lot of evidence produced from his sides that we should be doing better. Phil Neville decided yesterday finishing inside the top 10 is a good achievement for Everton, and while it's hard to swallow, realistically he's right (voicing it in the first place though, not a good thing to hear from your club captain).
Moyes is a good manager, he's worked miracles with what he has at Everton, but his philosophy doesn't seem complete enough to be able to go the final step, whatever club he's at imo.