Speaking as someone who played quakeworld, q3, and cpma for years, where a complex movement system requires extremely precise inputs, here's what's important that I think a lot of OEMs seem to miss:
1. Bottom out feel and general studiness. We press down hard, we hold the key, and we alternate those presses. A solid thunk, reassuring you that the switch has been activated and will stay activated until you've let up. Cheaper keyboards flex, shake, vibrate, ping and resonate through the backplate/case, or move in general--the keyboard needs to feel stable 100% of the time. More weight helps here. People might prefer o-rings for typing, but when it comes to gaming, I think just about everyone prefers the accurate feel of a solid thunk.
2. Keycap quality/texture. I don't really care for keycaps with cut ridges or anything like that, and rubberized keycaps feel pretty terrible in general and wear like ****. Thick, rough textured PBT is optimal here, and this is where I feel like quality slips the most. This applies to the spacebar too. Before I had mechs, I would shine up a spacebar and WASD in about six months, which was extremely frustrating. When a keycap wears, it shines, and when it's got that shine, your fingers are gonna slip. No laser-etched caps either. Here was my Quickfire TKL after like, three months of playing quake? -
http://imgur.com/a/rwsLd - looks like ****.
3. Rollover/ghosting. This should be obvious in 2017.
4. Detachable wrist rests. Some people prefer them, some don't. I can't use a keyboard without a rest, it just doesn't feel natural to me. Leather would be best here, possibly a plastic, detachable wrist rest that is covered in a piece of 3oz vegetable tanned full grain leather. Manufacturing costs might be prohibitive, but in my opinion there is nothing that would last longer and feel better. Emphasis on detachable though.
5. Size/looks. The G410 is a weird shape. Wrist rest on the left, nothing on the right? Weird protruding handle on the left too, why? I can't use my own wist rest, and I can't detach the left side rest if I want to. It's just a mess, and I want nothing to do with it. Make a normal TKL board with some extras. Volume nobs are appreciated, weird shaped cases that are bigger and more unwieldy than they need to be are not.