Adaptations are a tricky business. Just ask Alan Moore or Uwe Boll – though, admittedly, not for the same reasons.
Promotional Art for Frank Miller's 'Batman Year One' Trade Paperback
At the best of times your source material has a rabid following who will, once you've announced your intentions, scrutinize your every move – down to the the colour of underpants your hero may, or may not, wear under, or over, their costumes.
And at the worst of times... well... you should click on the Alan Moore link (above) before you go on to the rest of what I've got to say...
Most times our worst fears are realised (see Uwe Boll for the worst case scenario) but sometimes... sometimes the improbable does actually happen... [full 'story' at Nuances]