Yes, I suspected that limits are dictated by historical accuracy. In this terms, general starting conditions of Commonwealth are probably still too good. But while it is good as games starting conditions, not necessarily good for whole gameplay. Going this way further, playing as Commonwealth we should lead the nation to partitions if we would like to be historically accurate, right? But who would like to do so?
I suppose this wouldn't be such big problem if I would focus on Central Europe region, as you suggest. But my lands are now stretched between Baltic and Mediterranean Sea, with my main army stationed in Athens. ;P In no way they can reach Warsaw if some bad events would occur there. What I mostly can recruit still by the moment are dragoons, with can't realy fight alone. Austria and Prussia are actualy my allies now, and till now rather solid ones, so I'm shielded from land invasion, but if French will land by sea, thats different story. Simply don't have men to protect all borders. Limits for Commonwealth are set such way, that there is enough line infantry for one full stack (balanced) army and a little bit plus. To make things worse, that "plus" was also fighting at Balcans And since this are reletively fresh gains, I can not simply march my armies back to Poland not risking mutiny in Rumelia. Leaving Athens and Istambul out of protection it is not that good idea either, since French can sail also this way. At least I persuaded Spain for peace. ;P Not sure what to do now, to secure my position.
This is strange that having such vast lands, and quite good economy, I can not recruit more men. This is why I think those numbers should be somehow fluent. I fully accept this static numbers if otherwise CAI would create those "magical" stacks, but otherwise it would be nice to have them fluent. Not sure, however, how to do it.