Yep, MoM is still one of my favorite strategy games, almost 15 years later. I just got back into it this week, and finished up two rounds as a Runemaster / Artificer / Archmage - one as nature / chaos / life, the other nature / chaos / death. It's a somewhat cheaty combo, since it lets you craft artifacts for your heroes for so cheap, but I love to run around with a gang of incredibly well equipped heroes. In the second game, I didn;t even use normal military units for anything beyond town garrisons to keep down unrest levels. I mostly choose my spell books for what abilities they will allow me to craft into my artifacts - 3 nature, for example, can let any hero have pathfinding to get around over twice as fast, and waterwalking to explore islands.
More on topic, those Great Drakes you summoned are among the strongest units in the game. Once you conquer one of the crumbly, greenish towers, you will be able to plane-shift through them to Myrror, and unleash flying doom on S'ssra's bases.
Myrror is a very cool place; it doesn't look like much, but all the roads there are automatically enchanted (0 move points to go down them), and home to some very powerful new races like the Trolls, which can be nigh unkillable with their regeneration, and the Dwarves, which generate double income from all sources and have incredibly powerful infantry. Also, the ruins and nodes there tend to be more heavily guarded than in Arcanus, though that's not guaranteed. I played a match where the first 6 or 7 nodes I came across (still on Arcanus) were all guarded by Great Wyrms and Sky Drakes. Not fun.