[Agema]

Heroes...

Free researchers are a tiny drop in the research ocean. You'll get them on average about one every 8-9 turns with Luck-3. Instead of taking Luck-3, you'd do better taking Magic-1.

And what are the heroes really giving you? E5 is irrelevant: you'll get E5 oracles anyway, and you've got Earth Boots. You can cast any Earth spell in the game pretty much with national recruits. W5 is more interesting, but you'll pick up W2 easily and W3 if you're lucky on nationals. Add the water boosters you've got W4 at least. However, water arguably is the least of Agartha's 4 national paths: you get more traction out of fire and death (and obviously, earth).

Where Agartha most wants water is if you take a dip in the seas. Agartha is a genuine Amphibious race. If you're near the coasts, you'd be foolish not to grab provinces. You can put PD on them, and build castles, (although you don't get national mages underwater, so you want a build on provinces with indy mages). You're no badly outmatched underwater that an opponent could expect to easily crush you.