Episodes 7,8 and 9 are already underway so that train cannot be untracked.
I dont know how true it is but on a podcast i stumbled across recently, there was discussion that Disney may make some long term strategic changes based on the financial outcome of Rogue One. That they might begin to pull away from the Saga Films and make the Stand Alone Films more of their steady diet. The Trilogy approach is not only exceedingly difficult to plan but also somewhat confining from a creative standpoint.
Early indications are that Rogue One is not only a success but that it exceed TFA as a film. And why wouldnt it? The spinoffs allow directors and producers to simply make good films set in the Star Wars galaxy as opposed to trying to mimic Lucas and straying from their own strengths.
The Sagas…sure do it but only if you have something truly worth doing.