So in that spirit of seeking facts - or at least opinions of professionals in the field - I have some more questions on the subject.
1.
a) Given that I've just discovered Stansted turns 28m passengers now on a single runway, is it too simplistic to suggest publicly that if Stansted can manage that, then Prague can certainly manage 21m on a main runway plus a reserve? What are the other possible variables when comparing the movement capacity of the two airports?
b) to whom is that question aimed? or rather, who might accidently take it as a criticism? I am wondering if the ATC organisation would be the ones that stipulate how many movements the Airport can schedule in, so they might be the ones who feel they are being unfairly compared with Stansted. Which then leads to the question, which authority regulates how many movements Stansted can safely handle?
2. Different question. Prague's prevailing wind is overwhelmingly westerly, and usually, to someone used to London, benign. So they use 6/24 90% plus times. But they switch to 12/30 when the winds make a rare shift. So what happens if they replace 12/30 with a parallel 6/24?. What if there is a nasty northerly? Do you pilots then just have to cope with the crosswinds? How big a deal is that, in flying terms? (this question applies to all single runway airports I guess)