The problem is not just scheduling and story, but also in Agents of Shield's
terrible ratings. There's literally no incentive for the movie people to have the AoS people cameo if barely anybody is watching the show to begin with.
You'll notice how the cast members of the show have now realized they won't ever show up in the movies and recent interviews with them have shown they've come to face with that reality. Hell, even Jeph Loeb (the guy who heavily used the It's All Connected phrase in order to make it look like Agents of Shield had some semblance of "importance" to the grander scheme of things) has now distanced himself from the phrase, whether it be trying to redefine what he meant like here:
http://screenrant.com/marvel-tv-crossovers-all-connected/
Or to flat out denying that he ever said it like here:
https://www.youtube.com/watch?v=rRWqSujO5-I
It's not likely the AoS crew will pop up in the movies. Hell, they're being prevented from appearing on the Netflix stuff:
http://mcuexchange.com/clark-gregg-...keep-coulson-from-meeting-netflix-characters/