The short answer is that yes, with a standard center drain, it would probably be very difficult to achieve the proper slope with the wood plank look tiles. A trench drain would work. Another option is to use a teak shower tray over a tiled floor. Here is a link that might be useful: Teak shower tray examples

Prior to our 07 remodel, we had cork floors in kitchen, DR, entry and adjoining powder room for 18 years. I loved this floor! We didn't treat it with much care and didn't receive care information when the cork floors were installed. So, they received a far amount of water when washed, no added finishes or refinishing. We also have a 22 pound dog who managed to scratch up a lot of woodwork around window areas. The floors held up well. If you'd look close (like eyes a foot away), you could see many scratches from a variety of sources. The excess water caused some seams to curve up a little (only noticeable with bare feet). I really wanted to put in new cork floors, but, got talked out of it by a KD who said colors/patterns weren't right for our new look. We put in porcelain tiles and standing on them hasn't yet been a problem. I probably don't stand on them for more than 90 minutes at a time. If I were to put in cork again, I'd use the floating kind and panels or planks. When replacing the old cork floor, everyone was predicting big problems if we had to deal with glued down panels. The old floor came up easy because no glue. Cork is much more forgiving on uneven subfloors than tile. It took about a days work to even out the subfloor for tile (involved replacing some plywood and a lot of sanding). One of my friends just put in a high end glued down cork tile and they now wish that they had gone with the floating option.

I think the issue is that gray wood - whether wood, laminate, tile or porcelain is a trend that is on its way out - or so the design pundits say. If you love the look do it but tile - especially tile in a shower which has waterproofing as part of the construction - is not something that is easily or inexpensively changed. I recently did a gut remodel and it's not on trend at all - I was a bit disappointed when I found out that one of my color choices (teal) was being shown as on-trend in design magazines LOL. So I installed what I liked as should you if the gray wood is a design you love and one that you aren't going to regret the decision five years from now when people are posting in houzz desperate to update their bathroom or flooring. I believe that showers with tile on the ceiling can look a bit oppressive - most people tile their showers to the ceiling but don't tile the ceiling itself unless they are doing a steam shower which has rigorous construction methods. How is the traction on the tiles being used for the floor? Tiles are rated based on their COF. My bathroom floors and shower floors are the same marble tile but they are small basket weave tiles so the grout provides a lot of grip. Prior to the remodel, I have 12" x 12" tiles which were slick and deadly as ice when I had wet feet.

Don't saunas have wood walls? My regular suburban house has porcelain wood tile floor in the front hall. It's obviously NOT wood just like Joys' walls will be. I didn't know this look was ever popular in a shower so I have no idea if it is dated. My shower was redone about 2000.