Scrap the 3 Test series? And replace it with what??
4 Test series. Despite many believing that even numbered series gives a greater chance of drawn series which simply isn't true let alone logical (given not every game produces a win), these are solid series. The only downside is that we try to fit two series in a summer along with ODI series and some T20Is.
Anyway, my answer is that unless you have a player who is horribly exposed by a particular opponent eg. Phil Hughes vs Chris Martin...then you should be keeping the same XI throughout your 3 Test series, even if you lose the first. If your XI was the best XI a week ago, does one loss really change that? One or two bad innings? I'm a believer in changing teams between series not during them. The only time I'd change it is like England and West Indies have done here, dead rubber Test. Then give players a rest, try out some younger guys etc.
But the fact of the matter is you're trying to win a series, and if you don't change things during a series you're just resigning yourself to that fate. It is possible to realise, a la UAE series, that you've got someone out of form and it all horribly wrong.
And what if you need to win that 2nd Test at 0-1 down, even assuming the pitch is the same type you are telling me you can afford to go in with several batsmen/bowlers who performed poorly in the 1st Test?!?!?! I'm not talking about singling out one individual who has a bad game, I'm talking about an unmitigated batting/bowling disaster. I don't buy it that you'd sit back and send out a side that failed to make 150 twice in the Test and accept a probable series defeat.
As for the "horribly exposed" bit, our batsmen were "horribly exposed" by Ajmal. Bell scored a whopping 51 runs in the series, starting with 0 and 4. He was Ajmal's bunny FOUR times in the series, both innings in said 1st Test.
1st Test vs Pakistan (in UAE)
Strauss 19 & 6
Cook 3 & 5
Bell 0 & 4
Pietersen 2 & 0
That's an awful lot of "faith" to go into a 2nd Test with (out making a single batting change) England put on their Bon Jovi, kept the faith, and while the 1st innings wasn't too bad the side was bowled out for 72 in the 2nd innings of the 2nd Test to lose by as many runs. Who could have
possibly seen that kind of collapse coming? Someone who looked at the above list of 1st Test scores and then saw Cook 7, Bell 3 and Pietersen 1 in said 72 all out perhaps.................
I'm not entirely surprised, England have stuck with batsmen like you advocate before, we've also collapsed quite a lot in recent years.
79 all out (2002 vs Australia away)
81 all out (2007 vs Sri Lanka away)
51 all out (2009 vs West Indies away)
72 all out (2012 vs Pakistan away)
May not seem too bad if you call it four times in 158 Tests over 12 years, but the truth is no decent Test side should be bowled out for under 100, even if the pitch is terrible then you should be able to muster 100. Three times in the past five years is not clever.
So the point of the above is simply that sticking with players doesn't necessarily help. It's a nice theory to give batsmen a run, I agree with that, but I think blindly just ignoring what has gone before is asking for trouble and that's what England got. By the end of the 2nd Test it was too late to do anything, like leaving two key defenders on the pitch very early in the game on yellow cards and then having to play the last hour with nine men. You might hope they don't get a second yellow, but if they're struggling against a particular player (or just spin in UAE) then maybe you're better off just hauling them out.
So in the UAE series I would have made at least one batting change, if not two. And it isn't just based on scores, it can also be based on how much they struggled in the balls faced. Of course two additional/alternative solutions are better preparations in warm ups, although those are not often good indicators, and playing that extra Test which means even at 0-2 down you get a chance to recover the series while getting two Tests to see where the problems are.