I think this is actually a good thing.
The show is still popular and you can now give the character's a break and come back with a great movie, which will be easier to do and the quality will be much better without the restrictions of not only TV but of the actual 24 concept itself, where everything has to take place in one day and their are 24 episodes.
With only having to make a two hour movie (give or take) the restrictions aren't there, they don't have to write or film nearly as much, and they aren't restrained by any concept anymore which gives them much more creative freedom.
They'll be a movie in the next two to three years and that will give Keifer a real comeback.