"I think in hindsight, a better approach might be to make common encounters quicker and save most strategy for boss encounters, which I think players are inherently more interested in."
Yeah, that's generally how it goes in many classic RPGs. In those games normal battles are often meant to test your long-term resource management over the course of a lengthy dungeon crawl, and over with quickly. A normal battle is like a gap in a platformer, a small challenge you're supposed to overcome in a series of larger ones.