Pretty good list. I agree that most of these are top notch ballads. Here's a few that belong in the discussion in my opinion.

Wonderful Tonight, Eric Clapton

Just the Way You Are, Billy Joel

Something, Beatles

Open Arms, Journey

Wild Horses, Rolling Stones

Bridge Over Troubled Water, Simon and Garfunkel

Can't Fight This Feeling, REO Speedwagon

Melissa, Allman Brothers 

We've Got Tonight, Bob Seger

Every time You Go Away, Paul Young

Against All Odds, Phil Collins

God Only Knows, Beach Boys