Hemsworth is a surprisingly good actor. Fillion has done a great job in a similar role.

MH and CF were effectively total unknowns. If nothing else, that could work again.

For a ST, I could see setting it 25-30 years later. It would be fun to see the old gang. With the new techniques, CF could quickly become a Hawt mature gal. She has the basics.

For recasting, I'd go with a saga remake-reboot. Whats the point in putting them in an ST when you already have great storylines in the OT and a PT that could use a reboot?

For a franchise like SW, why go with every 2-3 years? It made sense with HP because we follow him through his school years. I understand that a theatrical release makes about 90% of it's money in the first three weeks. There's enough time starting around May 22 to do 3 limited engagement releases in the summer blockbuster season. They could all work from the same marketing campaign. They could be re-released in the last half of the summer. You already know that there is almost zero chance of losing money.