I don't think England will risk dropping a seasoned veteran like Collingwood. He definitely is struggling as a batsman but he is a tough nut to crack. I still expect him to play at least one match saving innings in the Ashes.
Therein lies a connundrum. People say Collingwood plays well with backs against the wall, you expect him to play "at least one match saving innings" and yet if the batsman were doing his job then England wouldn't be in that predicament - him and the rest.
I'm unconvinced by Morgan, more suited to shorter versions of the game. This is backed up by an unconvincing average, albeit he hasn't played many Tests. Played only Pakistan and Bangladesh, since his 130 he's not passed 20 Fair enough he played well for said 130, Pakistan only managed 182 between them in their 1st innings, I'm still unconvinced he has the technique or temperament. I also wish England would become more consistent, I lose track of how many times we switch around between Bopara, Shah and now Morgan - I may well have forgotten others (like Carberry)
Now we've gone from one extreme to the other, picking batsmen and never dropping them having previously dropped batsmen before they had been given a chance, I think this creates a problem in its own right. Before batsmen never had more than a few Tests to succeed, now the batsmen are so rarely dropped (if ever) that when one is out of form the biggest stumbling block against bringing a new batsman in is you simply don't know which is more likely to succeed - an out of form batsman who may find form in the match, or someone who has either played before or not, but certainly not enough to be a sure success. That isn't to say batsmen don't get a chance like Trott, but for me there should be more scope to give batsmen chances. I thought Carberry might, not that I believe he is good enough, but his chance was one Test with the probability even if he'd played a second he'd be out before a third.
Same applies to some extent for bowlers, although they bowl enough balls per Test that you can't argue so much the opportunity is lacking. Are bowlers like Broad doing enough to justify near exemption from being dropped? Do we have a strong bowling attack because there is no automatic reserve to come in for injury or other reasons, that changes and has been players like Khan, Pattinson (!), Tredwell and Shahzad who have less than 10 Tests between them.
It's somewhat ironic because I'd say our batting lets us down a lot more often than the bowling, yet the batsmen rarely get dropped while we've used lots of bowlers since the 2005 Ashes, I'd guess enough for 4+ attacks compared to enough batsmen for two batting line-ups