I'll be happy to answer this...What makes a well cast Diana to you and what about models turned actresses appeals to that specifically?
1. She need to be naturally tall (No camera tricks. No platforms etc.), and when i write "tall" - I don't mean for a woman. i mean even amongs the common men. 5'9 is good .around 5'10 or taller is even better(Courtney Eaton is a good example. So is Charlee Fraser).
2. She should be able to grow up with the character, which means in my eyes - the actress shouldn't be older then the rest of the JL members' actors. So No 30 something year old actresses. Corenswet is 31, Alcock is 25, Merced is 23, Pierre is 31(John stewart - GL). The actress who will be the new Wonder Woman shouldn't be older then them - when she will be cast.
3. She should definitely be a better actress then Gal Gadot(She had a great look for WW, but there were times her acting was too painful to watch), But i also don't need an Oscar's caliber actress.