You're making way to many assumptions in you're arguments and it's not very consistent, no offense.
1. I already acknowledged that far eastern (or Indian) nations would have issues with Russia, but they have issues with every western major too - the difference being that Russia has a straight land connection, resulting in way more men being allocated to Asia. If you're being attacked by France, GB or Spain as an Indian or Chinese nation you wouldn't fare any better apart from the fact that the AI is amazingly bad at shipping armies. Every European and middle eastern nation should be able to stand against Russia, which fits with my experiences. I haven't played neither Prussia nor Sweden for quite some time, so I'm not talking monster discipline (although a lot of NIs contain +5/+10 discipline or morale bonuses) - the Knight's ideas aren't bad, no question, but they're not spectacular either military speaking. And since the nerf request is actually done by a Swedish player ...
Anyway, the main difference in army strength between nations, excluding the outstanding Swedish/Prussian bonuses are made by player choice - pick Innovative, Defensive, Offensive and/or Quality and every nation is quite formidable military wise, provided you don't lack behind in tech or unit type.
2. Even Russians have to split armies to siege your land - why on earth would you face a 400k stack if you don't do it deliberately, stacking odds in your favor? I really don't want to come across as feeling superior, but I just can't understand how that should happen. It's not like the AI armies run faster by default or anything. If a 400k stack is hunting you, simply run away and let them eat the 10% attrition - Russia has a huge manpower, but losing 20-40k men / month will kill even that one, not talking about WE. Once they start splitting there armies (and I haven't had a single war against any AI who wouldn't start carpet sieging sooner or later) you can chose the right circumstances for quick, decisive battles and stack wipes. If you have a nice, mountainous province and a reasonably big stack yourself you can even take up the 400k and enjoy ~40 WS from one battle. Ofc you will have serious problems as any Asian nation, but again - that's not because Russia is overpowered but because you're Asian and they are the only major who can really get some serious manpower to Asia (because they can walk there and don't have to use transports) - If 200.000 Frenchmen would come it wouldn't be any better than the 400.000 Russians (although I haven't actually ever seen Russia go to India in any game whatsoever).
3. You have an interesting approach to your conclusions. My last two games were Granada and The Knights Hospitaller, both of which saw a huge HRE form by 1600-1650. In the first I did not fight Austria at all, apart from them joining Castille's wars as an alliance partner (which does not grant them IA), in the second I attacked them only after the HRE was formed. Fun fact: in my very own Russia game (which I abandoned by ~1600s for several reasons) the HRE formed in 1560! without me ever interfering at all. Basicly, the HRE tends to form in almost all of my games, doesn't matter who I play (although I tend to not play far eastern and Indian nations, as stated before).
4. It's relatively easy to do the catch up game if you westernize early, since you will have some nice neighbor bonus stacked up. I did not find that to be a problem most of the time, at least not for everything down to Muslim tech group (haven't played worse).
Apart from that this argument is probably for nothing since you obviously can't be convinced and neither can we. I don't think Russia is stronger than the other majors, you do otherwise - that's just to bad. Most of the time a read posts about militarily overpowered nations it seems to be mostly an issue of understanding how to win wars and battles and how to optimize your army. If you pick the right ideas, get a good army composition and know how to outmaneuver the AI, most wars become manageable. I'm afraid this might sound like bragging and if so, please accept my apologies, but with careful planning it is almost impossible to lose against the AI even it they outnumber you badly. The exception are the first 50ish years, were manpower can be precious and you don't yet have had the time to stack up the right ideas to wipe the floor with your enemies - but you rarely face worse than 2-1 odds by then anyway, if you don't play reckless, which should still be manageable.
PS. I would like to know how a 400k stack is supposed to take no attrition. That really sounds like a lot of bias. And btw., Prestige increases your max morale.