Completed my campaign with Morocco(lost of course).
It was a 30/15 unit campaign.I can say its a little OP because AI masses the army stacks and you have no chance.
Playing with small nations is almost impossible to win,due to financial limitations,even if you play agressive.
The two pillars that make campaigns unplayable are 1)the very limited amount of money you get that is caused from political stability,VDM bad options,large navy upkeep,and limited trade profit.
The only amount of money you can get is mainly from sellings techs.Completing VDM missions gives you some money but generally this is very limited.
2)the second problem is stubborn foolishly war declarations from ai.Its ok ai to be agressive but sometimes even if you pound them and they lose the war they dont agree in peace.Wars continue for ever ,even if their attitude towards you has become indifferent and friendly.Game mechanics needs a way to counterbalance this.
As we all now diplomacy is somehow broken in this game.The only way to fix ai stubborness is to improve their opinion towards you.The only way is to BRIBE THEM using the GIFT SYSTEM!But because gifts are expensive, human player must get more funds from giftsystem,coinage, mission system, and trade.
So to sum up i suggest
1)Huge boost in financial system for human,its absolutely crucial if you play minor singe-regioned nations.
Trade, and vdm mechanics should provide more money
2)Find a way to persuade the agressive AI to join you or stop being agressive.gift system should be used alongside with some bonuses from completing proposals with human andgenerally having attained agrements with you.
3)Prestige system is off.Can we find something to reactivate it.EXAMPLE GETTING SOME money or bonuses when you climb higher the prestige ladder
4)Somehow human allies must be more helping in wars.
5)Solve the problem of ai not guarding its ports
6)Ammo should be increased depending of unit training level
7)No suicide cavalty charges when ai defends
8)ambush mode could be reactivated,some units may get stealth capabilities
9)deployable land defences should be back
10)more casualities from shooting aboard in naval battles.Maybe naval upkeep must be reconsidered
11)rakes should get sabotage army abilities,hope can be done
12)more lenient diplomacy,more proposals,ai doesnt accept when you offer him a region!