I think some people are mislead about keyboards and this game. Mechanical keyboards aren't optimal for WA at all, not to say people can't rope well with them, I've got a Das 3 with MX Browns and they're considered a great all rounder for typing and "gaming", unlike blues which have an uneven release / activation point, if you can ride the activation point on Browns / Reds etc you can have as fast response as any keyboard, but the thing is it's too hard on Cherry switches. I did use red o-rings on it for a while a long time ago but I find 1 it turns a mech feel back into a squishy rubber dome and 2 although it does slightly reduce the key travel I found it didn't help at all with performance.
The key travel is far too long, the spacebar is clunky and wobbly, I've had the Das for 6 years and still can't reliably ride the actuation point because of this. I think they do fine for FPS gaming where WASD etc works fine, but for fast / accurate tapping I'd use something else. The Cherry switches are designed for good typing feel and offer no advantage whatsoever over a standard membrane KB. Of course when they go mainstream in this day and age gaming companies are going to take advantage of it and make it seem like the next best thing, just like 12000 dpi mice running @ 2000hz.
As for PS/2 and USB, PS/2 are technically better (I ran the Das on it for the sake of NKRO, and why not if I have a PS/2 port) as it's interrupt driven over USB polled, so if it's possible to use PS/2, aside from hot plugging it's better regardless, but you won't notice any difference in latency when gaming, wireless I'd avoid everywhere (input, network etc) if you care about stability and latency.
While I'm nowhere near the best roper I like to have a setup for as close to zero lag as possible for gaming in general, like using a CRT monitor with high refresh rate, I have a custom minimal windows XP disk just for WA and Quake that's tuned for lowest latency (Vista, 7, 8 and 10 all have input lag and high DPC latency). I mod all sorts of things to make them better, it's just a hobby really to aim for perfection.
With keyboards I think the scissor switch will always be most optimal default because of the low travel as long as keylock doesn't interfere, I tried roping with mouse clicks before which worked ok for response (I modded the switches inside to fast responding ones) and felt quite natural as I use WASD for movement but I found the clicks just weren't smooth like a keyboard and it felt still a bit slow.
I've tried the paper ball method under the membrane of rubber dome - this one is probably the best mod you can do, but it has to be done right, as you can make the keyboard as responsive as you like (even touch sensitive) but I think you have the get a good hard wearing object underneath that isn't going to shift over time for it to be reliable. This method could probably be unbeatable if you took the time to set it up right.
Standard rubber domes I find vary loads in how sensitive they are, some are lower travel and soft, some are really stiff either by default or where the domes have aged, but they're still in general better than mechanicals because of how fast the dome snaps back.
Last year I switched my Das to a HHKB Pro-2 which has Topre switches and it's USB, I've dental banded them (sort of similar to o-rings on cherry, but they don't affect the feel of the key when bottoming out) which reduces the key travel slightly, I find the Topre amazing for response as they're a mix of spring and dome and make no contact on actuation, they also bounce back really fast with very low tolerance (no wobble / rattle), basically they blow Cherry out of the water for typing feel and key response (makes Cherry feel like a cheap toy).
I've never tried Alps switches so can't comment on them, also buckling springs I haven't tried in so long but I'm pretty sure they're crap for anything other than typing because of how stiff they are, also the Model M has I think very low key rollover (2 or 3 I think) although the Model F has NKRO and also better switches.
Just thought I'd share some of my thoughts on keyboards and stuff, basically in terms of maximum possible tapping speed and timing accuracy, I would say the #1 keyboard for WA would be a decent modded one with an optimal object under the membrane to make it touch sensitive. As long as keylock doesn't come into effect either that or naturally the next best thing would be a low profile scissor switch board.
Cool story. But yeah sorry mechanicals are better than whatever you described and Windows XP is garbage, majority of people can't even use Windows XP on their PC's because their motherboard doesn't support XP drivers... lmfao... an OS has nothing to do with improving your skill and if you think so then yeah ummmm cool bro. I'd also prefer my BenQ 24" widescreen at 144hz that smokes your CRT monitor that is limited to 1024x768 while I rope on 1080p. Also, the DAS and HHKB are probably the 2 worst mechanical keyboards you could buy, along with a razer.... if you're buying those brands out of the majority of well respected and better build quality brands you definitely have no idea what you're talking about haha (and im not talking bout gaming company brands). As far as your "analogy" or whatever it was about 1200 DPI mice... some people benefit from high DPI if they play games on resolutions higher than 1080p... or just general use of their PC on a large monitor. Hence why most mice are sold at 400/800/1600/3200, to give the customer an option or be able to switch. Just like mechanical keyboards, they not only offer good cherry switches, you're able to swap them if your board is PCB mounted, or you're able to replace ABS keycaps with PBT keycaps. You can do whatever you want to your board opposed to staring at a piece of shit that just lags and has keylock. Sorry but it's 2016.
Also, I've tested scissor switches side by side with my mechanical... and it wasn't better. It's all personal preference dude.... I like high keys and some other people don't and some do, it's a matter of taste of what you have the feel for with being comfortable. There is no best keyboard to use. Period. But what I will say is that mechanicals are the best thing on the market and will stay that way. Cherry switches blow your paper method out of the water and your 1999 keyboards you think are good cause they are Ps/2 hot wired when you have no understanding that the vast majority of USB keyboards poll at a 1ms response time... lmao... sorry I don't enjoy having 2 key roll over on those shitty old keyboards. You can disagree with that all you want, I don't give a shit. Lmao.
Model M keyboard is the perfect keyboard if you use 1 finger only, the control and activation point is ridiculous accurate. If you twitch or fingerroll however, it can't handle high speeds as well as others due to the buckling spring tech. Also, the contacts on Model M are insanely responsive, unfortunately it's a pain in the ass to remove the keys to get access to them.
In terms of modding, it does not matter what tech a kb uses because the best mod is tapping directly on the contact without any sort of object, however it requires 1. big contacts (such has the Model M, IBM rapid access, some Logitech etc.) 2. small fingers, if your fingers are too big you simply can't hit it and 3. even then you need a lot of practice to hit the keys. It took me a couple of months to even get good at this method of tapping but it's the best you can get in terms of responsibility , reliability and accuracy.
So, in the end the best mod, is to not mod, kinda. Simply remove all the bells and whistles and enjoy the inner life of your kb and get accustomed to it.
Model M is not great for double tapping, it's very tactile and clicky and has a lot of hysteresis, it also only has 2KRO. So your Model M (which is a mechanical keyboard, lmao) is basically like a Cherry Blue... lmao? Please get an understanding of computer parts/accessories. You probably bought your PC pre-built.