Hartley also made 145* or something two matches ago. Averaged 34 last year and has generally been acceptable. His keeping is much, much better than Haddins (which brings value of its own).
Nevill is a good bat, averaged 40 last year and a 50 a few seasons ago, had a poor 2012/13, he'd do a reasonable job.
Haddin, on the other hand, may average 34 but he' only averaged 30.4 since coming back into the test side (over the last 16 tests). He scored just 500 of the 821 runs in that time in 5 tests in Australia, otherwise averaged 20 odd in England, under 12 over his past 5 tests. Of further concern is him getting bowled alot of the time - a sign that the reflexes are on the wane, something also evident in his keeping in the UAE.
Haddin also only averaged 23.5 before his replacement by Wade (his keeping also poor then) - it was a reasonable decision that didn't work out.
I'm happy for Haddin to be there in Clarkes absence, because I don't want Smith captain yet (have huge wraps on him, think it's better for him to just keep concentrating on his role as a batsmen at present). His career average of 34 means shit at this point, he's been on the wane, outside a magical series against England last summer, for a long time and he simply isn't way ahead of the competition.