I think problem is not in development but rather in the way internal politics are in the game. Commonwealth in real life had huge struggles with nobles. Sejm was lazy not paying taxes and refusing to fund army of country (which was already small due to lack of funding from them) and used VETO power more than anything else. In game Commonwealth has no such problems, you can easily raise huge army, you get huge income (irl Commonwealth all nobles had no taxes).
Wrong on several fronts: they paid taxes, first VETO was enacted in the second half of XVIIth century only, etc, but I agree that the problem is that of internal politics which (does not) exist in game.
Most of other "historical" arguments presented in this thread, and I deliberately use "", are correct for second half of 17th century and 18th century, but not for 15th century! Starting game in 1444 it is possible to "centralize" Lithuania, to make it use its potential etc. It is not preordained that country X will fall (unless of course it is a target of Pdox magical DHE events like burgundy).
I have seen that several people said it before, but majority ignore it repetitively
- game starts in 1444 and not to say e.g. in 1667
- big part of "Russian" land was not under control of Muscovy in 1444 (vassals & minors, Novgorod, Khanates, 1/3 of Lithuania) - so comparing development of Muscovy and Lithuania in 1444 is a complete nonsense; Muscovy centralized and took over a lot of land with population while Lithuania decentralized and lost population (Similarly France does not own its all 18th century cores in 1444)
- prevalent socio-economic model in Eastern Europe was completely different than in Western Europe, there were only a few big cities and majority of population, taxes, production and whatever came from countryside. Nobility "actively" fought against burgers and won that fight. They were allowed to establish whatever production they wanted on their land - using peasants for work - thus completely cutting guilds out. While in Western Europe cities in Lowlands, N. Italy etc became powerhouses, in Eastern Europe they became marginalized.
- development can not be selected to force preferable outcome after 350 years of gameplay
- Lithuania had potential to became great, Vytautyas was close to dismantling Golden Horde and absorbing part of it but lost at Vorskla river
- 40 years before game start it was Lithuanian which was expanding against russian principalities: e.g. Vytautyas incorporated Smolensk in 1404, in next 5 years fought with successes against Pskov (which forced to pay tribute) and Muscovy, in later years Lithuania established control over several other prinicipalites and for a short time even over Novgorod. Nobody can say what would happen if Grand Dukes remained independent of Poland, but one can guess that catholicism would not be so powerful and with equal or even preferential treatment of orthodox nobility integration of Ruthenian population would be smoother (or assimilation would even proceed in opposite direction)
I am not saying that Lithuanian development is ok since I have no idea what criteria were used to assign it. But the voices "nerf them" are on par with Horde units pre 1.13, native ability to colonize and cross water etc.