An air carrier Captain on the PHX GEELA 4 RNAV noted that the DESCEND VIA clearance was modified by numerous altitude modifications and caused great confusion.

Narrative

The Approach Descent system with 'VIA' attached makes for a confusing approach for all involved. I continuously hear controllers and pilots alike re-confirming their clearance intentions. It promotes frequency clutter and I believe makes for a hazardous approach environment. We started the STAR with a limited clearance to FL250 and speed adjustments. Then once past the first restriction; ATC delayed our descent; putting us high on the profile. More changes to the STAR ensued. You get to the point where the controllers seem to be flying the airplane. With each change you don't know if the next altitude assignment is now a simple descent or a requirement to descend and still make the crossing altitudes on the STAR. Meanwhile you're alternating between VNAV and LVL CHG for vertical guidance. It leaves you in a continuous state of doubt. You can only hope that the Controller has control of the separation as some planes are on VIA's and some are not and the Controller asks for re-confirmation so many times you wonder if he's certain who's a VIA and who's not. In our case we were given a hard altitude of 17;000 coming up on MNSTR; and then cleared to 15;000. The descent was delayed for a short moment because we were in ALT HOLD; not VNAV; and it took the First Officer a moment to realize that. None the less; the Controller was quick to confirm we were descending. MNSTR calls for a crossing of 160-150. The Controller never said anything about making the crossing after he held us up for the umpteenth time; but I can only assume he thought we should make it. Obviously; there's no way we could make it being that we where so close to the fix. The last change took us off the STAR all together as we were now Radar Vectored to Runway 26. While I prefer that runway anyway; this last change just served to underscore the issue of way too many clearance changes on what was designed to be a smooth VNAV approach. In short; it is the process of assuming where and what everyone should be doing on these VIA approaches that bothers me. I vote that we eliminate the VIA approach not because it's a bad idea but because it's a communications hazard. You rarely get it where you can truly fly it as published; so why even have it. In fact wouldn't it be easier for the controller to simply say cleared to 5;000 on the STAR instead of confirming and re-confirming that each airplane has the semantics correct. At least then they're would be no doubt for the controller or pilot as to what the final altitude is supposed to be. Let's return to the KISS concept and keep it simple. Keeping it simple promotes safety!!