I used to be in the lightweight, low recoil, camp. Shot a .243 HandiRifle and loved it. However, hunting deer and hogs in thick, wet terrain convinced me of the value of overkill and mechanical injuries. I shot a nice buck this past January that I KNOW is dead, along with several nice hogs. The buck in particular I watched go down, but lost sight of when I climbed down and had to wade a creek. I'm convinced he's still in the Cypress swamp somewhere, rotting. No blood trail in water, folks.
I went back to a 30-06, the biggest caliber I can comfortably manage. I encourage others to do the same. 5 months later and I'm literally still dreaming about that buck. A thread a while back talked about how many mature buck sightings folks had each year. General consensus was 1, 2 if you're lucky. All the plotting and planning, all the tired and freezing, means NOTHING if the animal can't be recovered.
I do not doubt the ability of a .243 or similar to kill deer under most circumstances. But those exceptions to the rule can haunt you.