Well, just for this reason I made a test in a relatively poor region. As Eastern tech Ragusa I conquered about 40 provinces, I think my base tax was low, averaging about 3. I converted everything to Reformed, culture converted everything I could (except for Constantinople). Grabbed Economic and Quantity and built absolutely every building I could.Recently I thought about this subject and went to conclusion: you can't make your state a great power in a peaceful way. No chance, because you need that base tax from other provinces. You can't raise BT of your own territories (except temple) and create a super-nation Greece (for example) with a decent army and fleet only because you are restricted to mediocre-BT provinces.
I wish I could spend ADM points to improve my provinces (build new cities and their improvements: schools, roads, churches, colledges, some manufactories) in a more reasonable way
For example in CK2 you can conquer all Mediterranean islands, build more temples, cities and castles, upgrade them, and you will be on par with the whole African Emirate in terms of troops, and you have a chance to add territories in a peaceful way.
I finished #2 behind a huge HRE united by Austria (force limit, manpower, income). I couldn't really risk super interesting wars (a sort of global militia a la UN) because manufactories especially take a long time to make and sieges halt their progress, plus you lose it completely if they win the siege. Also culture conversions suffer from the same disease.
The only problem with this is that it was super boring.
It only got interesting because the AI underestimated me and declared war 4-5 times.