Pray tell, where are you able to recruit tier 3 units? if you mean you grind looters every time until they hit t3, that's exactly what I am trying to avoid.
From villages and towns? I don't know where you're getting the idea high-tier units don't appear there, but they do.
At any rate, I'm just constantly recruiting replacements. I don't really care if I have 30-40 tier 1 units in my party or whatever because after a single battle (not against looteres), I'll have 15-25 tier 2 units instead.