I've got a case. I've hopefully found a cure, and that's a 50/1.4 that is now glued to my camera. The zooms open up a lot of possibilities but I am finding that they are restrictive as well
A 50/1.4 has an incredible zoom mechanism, albeit manual. You step forward to get closer and step back to zoom wider.
I don't think about what I am doing but react to a given situation or worse yet, try to create a situation. I've gotten frustrated compositionally and too taken with "the image" and trying to construct it rather than recognize it.
As to the quandry here, well if you are simply finding and not crafting a composition in your mind, then you are simply taking snapshots and not crafting photographs (anybody can cook with $1000 set of saute & sauce pans, but not anyone can cook fine cuisine with them). This frustration is a hurdle your mind must cross to reach a deeper more intuitive understanding. Study it some more and then step back and let your subconscious mind process it for a while and enjoy a day at the beach, a long bike ride, a hike, or a jog w/o the camera and be in the moment without worrying about composition. This periodic step back to view things from a wider perspective intellectually and emotionally is vital to mastery of a subject.
As a practical step, you should learn that
the angle and distance of your lense to subject determines the composition (relationship of elements in the frame) while
a zoom simply changes framing (wider or not so wide). You can simulate zooming in by taking two steps back with a fixed focal length lens and cropping to get the compressed perspective. Or you could shoot a handheld pano (Photomerge in PS is pretty good) after stepping forward to simulate a wider angle (albeit wide angle distortion is lost).
Until you have reached the physical limits of your lenses, getting more lenses with only add to the confusion of learning to compose rather than helping. Get a new lens if you want snapshots, learn to use what you have if your goal is to take photographs. Any competent photographer can take beautifully composed photos with a $5 disposable camera.
It is a long hard path to journeyman status (mastery is the ability to train, not the ability to create) and mastery of a subject is years beyond that. But attempting to learn to use yet another tool (lense) before you can fully use what you have will make the path of learning wider, the learning curve steeper, and just add confusion to an already challenging subject.
Additionally, FWIW, zooms are prime lenses. Only things like diopter filters (close up filters), 1.4x & 2X extenders, and other such add-ons to primary lenses are not primes. A 70-200mm zoom is prime lense. A 1.4x tele-extenders is a non-prime lense.
more concrete idea to follow,
Sean