Medium is around where I've located myself with the now mostly working AI too.
1 v 1'ing on some of these 2 v 2 maps can make map control quite the hassle, yes. In fact, it's too much of a hassle for me, and I don't 1 v 1 any more. So everything I've said does run into the wall of actually being able to position your army (or armies, due to map control requiring some splitting) in a spot that can take advantage of any abilities you own.
For instance, I've once demolished an enemy blob with the armor's shock wave, but it was the Dragon's Pass map, where the main armies naturally meet along the Z.
In theory, and in practice when you manage to outmaneuver your opponent, mass damage weapons are natural anti-blob measures. Juggernauts, Devastators, Shaman paralyze, Zeppelin mustard gas. These are, as you've noted, more late-game techniques. Early game, it kind of comes down to how you manage your armies and how you micromanage fights, as you struggle to achieve a high kill-to-loss ratio.
As you've noted, the AI builds as it fights, something only a really skilled human can do right. You've also got to survive at least one onslaught before you can even bring in your dragon, which requires its own research or cards to be useful.
