I tried it against myself. Twice, the Blind spell activated on the Archers, and as a result, all the Elves, Gnomes, Pegasuses, and 24 Treants survived :cool: ... The tactic was simple: destroy the ranged units with fast units in the first round, and then defend. The main goal: leave only one stack of the opponent's units (in this case, 17 Archers), and then collectively take them down... That's how it worked.
It's also very effective to Entangle these Archers :).
In my case, the Blind spell activated on the Archers once, but it still significantly changes the outcome of the battle. Without it, the Archers destroy everyone :).