Byrne #1? really?
I thought if anyone was going to question that it'd be you.
Ounce for ounce, pound for pound - JB wrote some damn enjoyable comics. His 'try-out' issue in Marvel Two-in-One 'try-out' issue is a genuine classic. His Fantastic Four was near flawless. Namor is still the best Sub-Mariner series of them all. His Superman, Adventures of Superman & Action made Superman meaningful again. I loved his Wonder Woman. Iron Man, New Gods, She-Hulk, The Thing, Next Men and of course (just to make you cringe)... West Coast Avengers!
And while not included in my list he was equally great when co-writing (with Stern on Captain America and with Claremont on X-Men/MTU/Starlord).
Sure, just like every other writer, he's had some duds, but just because he's many people's favorite target to bash, doesn't erase in my mind the excellent volume of work he has done.