Okay, so Indra and I tested it out.
We didn't finish the game, but it seemed like it would be an easy win for blue.

Here are the conclusions I drew after discussing it with Indra:
When a Ranger gets Water Mastery at level 4, it might be worth taking it. I kept getting it shoved down my throat every level until I took it as the lesser of two evils. Otherwise, Earth might have been a better choice. It was very important in that game.

And secondly, you can explore other spawns, hidden areas, and try your luck. I often don't have the patience and I engage when the opponent has an advantage.
Indra, on the other hand, was running around, gathering resources. It didn't help in this particular game, but it's generally a good move that I need to learn to do when the game situation requires it.

My opponent in the beginner game played a great blue deck much more slowly than I did in the game with Indra. And if I had followed the conclusions above, I might have been able to win that game.

That's it. Thanks to Indra for his time.