The Time Ships by Stephen Baxter is an excellent novel adored by millions. We believe that it woulld be an entrhalling movie due to a an rollercoaster plotline, amazing set pieces and the way in which it embodies and improves upon one of the original science fiction masterpieces, "The Time Machine".
Visually it would be spectacular.  The world war scenes alone merit a short film.
The time travel sequences are longer and more vivid than those in the original novel, and would allow a skilled movie maker loads of room to showcase their talents.