Sorry to hear you didn't enjoy your stay fully. I won't go into the design issues you pointed out as that can be very different for people with regards to likes and dislikes, e.g. the bathroom topic. To keep it short, for us personally the rooms work quite well and offer a very good size for Japan (~50sqm for the Premier ones) though I hear you on the table & chairs for dinning, it's lack can be tricky for some and yes the residences offer a better set-up in that regard or at least the King Jr Suite with the separate living room (57sqm).

My wife used the very nice pool, I used the bath house and overall, including gym, the whole wellness area is great for a city hotel in my book.

Not sure what was happening at the hotel when you were there, but we stayed 4 nights in 2nd week of Nov and on 2 days IIRC the hotel was full. Never waited more than 2-3mins for a table (for 2) at breakfast even when showing up between the busy times of 8-9am. So definitely not a useless Diamond benefit in our case. For anyone familiar with the a la carte menu, it has been "shrunk" a bit with regards to options with the main missing item being the Egg Benedict with the short rib that was a signature item before. It's gone, for now.

Overall, for us this is still our most preferred hotel in Osaka as location, hard & soft product all work. Pricing is a bit steep as in all of Japan now, so I'm hoping my employer's corporate rate stays within reason. YMMV.