While avoiding weather on the EAGUL RNAV STAR to PHX; the flight crew of an A320 and ATC suffered a communications breakdown with respect to the expected descent requirements.

Narrative

Inbound to PHX it became apparent that there were thunderstorms on the EAGUL arrival. The left was clear but this is the departure corridor and we had to stay to the right of it. On initial contact with Center at FL340 I asked which way guys were going. The Controller said cleared direct HOMRR and deviate as necessary. I was not given a descent clearance but it may have been blocked. We entered direct HOMRR in the box. Doing so; of course; wiped out all the intermediate waypoints and we were just passing SLIDR. We asked what altitude should we maintain and we got a lecture on how we had been cleared to descend via the EAGUL 4 26 transition. I told him that going direct HOMRR wiped out all the constraints. I then got a second lecture on how we were cleared to descend via the EAGUL 4 26 transition. We had to deviate right and then left and then back right to HOMRR without a floor on how low we could go. We were very far from the next constraint VNNOM which was between 11;000 and 10;000. We became VMC and just guessed at what altitudes to stay above; not wanting a third lecture.It seems the PHX RNAV STARS have not been fully developed. ATC controllers need to understand how Flight Management Computers work.