Valid concerns, for what it's worth I've had my own suggestion for this mater:
basically: outside of the rng generated generals (wich in this mode while having random IG's would be weighted to have better traits) there would also be a section of "politicla appointees" basically an extra pick per IG in goverment, these generals would either be weighted to having worse/less traits than the rng generals, alternatively they would have a "political appointee" trait gives reductions in promotion and beurocracy costs in short buff that make them better at sitting pretty rather then actual warfare.
taking a page from yuor idea and victoria 2, literacy affects both the quality of the generals available (tough obviously the rng ones would benefit more from it than the poltical appointees) but also the number, so one can relatively rapidly run out of competent rng generals, or even of rng generals altogether, while the player never runs out of political apointees (shortages of officers where a thing in this period but never shortage of generals) each apointee recruited, decreases the quality of the next one (wich replenishes overtime), the goal of the desing is that also make the political dynamics of the country affect the officer make up, since the quality of political apointees
is determined per slot ( so even with high literacy if you keep mass recruiting officers from the Landowner IG eventually you will start drawing atrocious generals, wich has the side effect of encouraging authoritarians countries to keep few generals of verry high rank which is appropriate) this means that democratic countries by virtue of having a usually wider pool of political appointees can better bear the cost of a massive military expansion (say creating a large number of conscript formation before a war and so on)