Can't figure out what I'm doing wrong

[Sencha]

Thanks for the advice, I'll definitely take it into account. I guess I was overestimating the importance of taxing and temples. So I'll ease back on them. I'll also increase my research staff, hire mercs more regularly and try to capture more provinces per turn.

I'll also try to use my Pretender more directly. I could have guessed that holding him up in the castle probably wasn't making the best use of him, but I was afraid he'd get killed in battle. (I've seen it happen, probably b/c I didn't design and/or equip him to be a SC).

As for my game settings, I didn't touch the scales much, (don't remember my exact settings), used a medium map and I believe the AI level was default.

[Taqwus]

Early on: yes on mercenaries, not temples.

Being able to recruit a priest with fire/holy leading 100 pikemen for in the whereabouts of 600 gold (AIs are not generally aggressive bidders) in one turn even in the lowest-resource province can jump-start your expansion. Sure, you're renting them. Renting troops to take the initial charge of independent knights, however, might end up being cheaper than sacrificing national troops.

It should also be noted that some Late Era nations will have large armies full of low-quality troops -- don't bother trying to match the Ashen Empire or the Dreamlands (Late Ermor and R'lyeh, respectively) in quantity. Crush them with quality. The AI in general will also pay much less attention to research and mage support... or supply... then you might, too.