We have a walk-in shower. Designed it and had it built into our house when we had the house built 18 years ago. It is an oversized shower (dimensionally). The shower head is on the same wall as the walk-in doorway and directs water towards a ceiling-tall ceramic tile wall directly opposite the walk-in "doorway." There is no door.
The plusses are (1) there is no door, and thus no soap film to clean. There is just a 4" tall threshold for stepping into/out of the shower stall. (2) The entire shower is encased, floor to ceiling, in ceramic tiles (20" squares) which are very easy to keep clean (no soap film). (3) This design also ensures zero water is splattered onto our bathroom floor.
Our design started with the builder's "standard dimension" walk-in shower (that included a shower door). The ceiling height in this shower and the master bathroom is 11'. Then we expanded the shower walls by 1 1/2' in both dimensions (now 4'x 7'). So, three of the shower walls are complete floor-to-ceiling height. The wall opposite the walk-in door has an 8"x30" window about 9 feet above the shower floor - that wall is on the north side of our house, so ambient light is indirect. The fourth (showerhead) wall is constructed similar to the other three but has the doorway.
This design provides us plenty of room for whatever we want. The only thing we might have changed would be to add a bench on the wall opposite the showerhead. But otherwise, it's perfect. Kudos to my bride: she imagined/designed this shower. Our builder liked it so much he offered it as an optional feature for his other floorplans.
This is great for us (both now in our late 70s).
We have a walk-in shower in one of the other bedrooms. But it is a "standard dimension" (3'x4') shower with a glass door/wall. And it requires the usual amount of periodic scrubbing.
We started with a standard builder floorplan on a 1/3-acre corner lot. Then we expanded the exterior walls to give more space in the great room, the master bedroom and its two walk-in closets and the laundry room, and installed hardwood floors everywhere except the ceramic-tiled bathroom floors. We raised the ceilings in all common areas and the master bedroom to 12" while the other bedrooms and study have 10' ceilings. And - my demand - we expanded the attached tandem (3-car) garage walls to increase the square footage to that of a 4-car garage. In this expanded garage I installed a wall of built-in storage closets, two rolling tool chests and a refrigerator. The entire garage is painted/textured drywall, and the garage floors are epoxy coated. We park our cars on 2X3' rugs to prevent tire weight from destroying that epoxy coating.
This is the 5th house we've had built and incorporated all of the design elements/dimensions lacking in our previous builds. This one - a 3,000 sf one story - with 3-bedrooms (each with an ensuite bathroom), a large kitchen with floor-to-ceiling built-in cabinets and a 3'x8' island, an attached 800 sf tandem garage, a 12'x12' study, a 12'x14' formal dining room, a 4th bathroom adjacent to the laundry room and garage door, and two 12'x14' covered patios - is (hopefully) our final house.
This is experience talking, listen and learn or take your chances. 
