I am not a pro, but I would be turned off by a shower that is smaller than 36" square. I would also be wary of a DIY shower -- waterproofing is something that must be done correctly or else there could be the risk of serious water damage.

With respect to your layout questions, I think you will get better responses if you post a to scale drawing of the space.

I think you should post layout with dimensions to receive any kind of helpful input regarding new layout.

However, I can't imagine a shower that is smaller than 3' x 3' - even that size is not really adequate in my experience as bending down or moving arms around is problematic. I had a larger stall shower in the guest bath and a crappy tub/shower in my master bath prior to my remodel and the tub/shower was nominally better because at least it had length if I turned as opposed to the stall shower.

Not a professional but I do have a 6X8 bathroom in a 1950's ranch. Take the extra area. Depending on what your codes currently state you may need to find smaller units to place in it. When looking to change our bathroom four years ago the plumber mentioned something about needing more distance between the stool and the sink, 18 inches.

I would like to suggest a shower running the length of the 4' rather than a smaller one. Easier for people to use and actually at least to me would look much better than one of those box showers.

A 3 x 3 shower is to code in my area and that's what I have. My husband was a big guy and it fit him just fine. I don't like large showers as I find them cold - sort of like standing in front of a fireplace and one side is warm and the other freezing. Same in a shower with the water on one side. I suppose it is sometimes fixed by having multiple shower heads on 3 walls, but that's a very expensive solution to simple problem - just make it smaller!

Anglo 3 X 3 is 36 inches square. The OP needs to check the codes before changing to a smaller size because some areas are more picky than others and when sold in a couple of years might need to be ripped out and redone.

One of my showers is 3.5' x 2.75', and the other is smaller by just a bit. They're fine. What are people doing in there that they need a gigantic shower? Unless a person has a very large body habitus or the shower needs to be ADA roll-in compliant, large showers are wasted space. But yea, always check code in your area.

I just checked on a tape measure and my arms stretched out are more than 36" and I am a fairly short person.

I also found it cramped when I wanted to lean down to do anything.

I can't imagine deliberately opting for such a cramped shower. To me a decent sized shower would be absolutely critical if I were looking at homes.

I've currently have a 36" x 36" shower and had a 32" x 32" shower for 43 years. The smaller shower was in a 3 sided alcove and the larger is in a corner, so two glass sides. Both are/were OK, no elbows hitting walls or anything like that, but I do like the larger one better.

For resale purposes, look around your area and see what is available in your price range. In my area, all the bathrooms in our size/price range (2000 sq ft, $900+K) are the dinky size we are talking about here, so ours doesn't stick out as a negative. If you anticipate moving in a few years, I say leave it the way it is. It's likely that diminished closet space may be more of a negative than a routinely small master bath. If you are staying for the long haul and making your bath larger would make it significantly more usable/comfortable for you, and you don't mind less closet space, go for it.

I had to laugh at what do people do where they need a larger area. I actually like washing my feet. I used to lean on the wall and raise my leg but now I have to bend over. In the smaller showers either my head or my butt touches the wall and I am short.

A 4' deep bathroom is too small. Minimum should be 5'

I took part of my closet to enlarge my master bath in my 1950's ranch ...

Before - with what I call the "coffin shower"

After ..

pamhatten that is the shower I was envisioning being placed on the 4 foot wall. While it would be cramped if room is left the current size enlarging it to the 8.5 or even 9 foot size should provide enough space for both sink and stool and to me look better than one of those box showers.

Oh, no doubt this BR is not to code. The distance between the bowl and the sink might be six inches. We could remove the freestanding Ikea closet (lower left corner) and build a custom shower that is narrower that goes all the way to that wall (total 4' wall to wall), but that tower closet is a godsend--besides under the sink, there is no storage in this bathroom. I didn't think a 3x3 shower was small--I've had those crazy small ones in which it's hard to soap up without banging elbows--probably 2x2.

I cannot seem to edit my post....so--we can live with the bathroom the way it is, but since the floor tiles are coming loose and we may potentially have to rip out the shower to rebuild/reinforce the floor underneath, we are considering improvements. Yeah--they did not get permits for most anything--we were smitten with the lakefront property, so we just went for it. Thanks for all your suggestions.