Fullsize keyboard - I have no idea TKL would be so much more ergonomic without the numpad. If I knew I would have get rid of all my full size boards MANY MANY years ago.
realforce 87 - I thought it will be the be all end all keyboard, it's very good no doubt but the medium thickness keycaps, the slow debounce (compared to mx) just make it less than ideal.
mx blue - For some reason the clickyness make it feels less "solid" and it wobbles compared to other mx, I hate the blues on the das.
mx green - I figure the heavier spring will make the wobbliness goes away but it's worse than blues in other ways. Its tiring even I just use pg/pd & arrows for browsing documents.
dvorak or any non-qwerty layout - The increased efficiency is an illusion, unless you're a writer and only use word processing software. Most of the software out there assume a standard QWERTY layout when they design w/ usability in mind. Ctrl-C Ctrl-V Ctrl-X, HJKL vim navigation etc. I spent a year with dvorak and although my typing speed increased, I didn't get my work done any faster because of all the customization that I had to do with my editors and software to make my computing experience not suck.
Same reason I stay away from GH60 and specifically HHKB layout.
blank keycaps - I can touch type just fine but I didn't realize how often I use one hand to hit the keys while using the other hand with the mouse.
Without the muscle memory (two hands with index on F & J) I can't really hunt the correct key I want

Still need to find a keyboard with clear to complete my evaluation of all common mx switches.