Dave, he's a wop from New Joisie, does that explain things?
To give ole Joe credit:
- He's a fine singer in his somewhat less than idiosyncratic AOR mode. Unfortunately, Lou Gramm was there before him.
- He was a member of the third major Rainbow line up that lasted with him from 1980 to 1984 (longer than all the others), which in Rainbow-terms is decades. He did what he was asked to do for Blackmore, i.e. AORize Rainbow for the US market as the now so hallowed Dio line up of Rainbow had gone nowhere in the US (Blackmore was losing money with the venture), Blackmore had become tired being the opener for bands like REO Speedwagon, he wanted airplay, a not just all-male fanbase and no more dungeons and dragons.
Your disdain for stadium rock accepted, even you have probably heard those two:
That's Joe on both tracks and he was pivotal for that line up's particular music, co-writing most of it. He also had a spell with Deep Purple as their lead vocalist in the early 90ies, a period most DP-fans like to forget about, but that is unfair IMHO, Mk 5 didn't do bad music at all, it was just very Americanized:
Blackmore and Turner never fell out (though I have a hunch that Blackmore doesn't take him quite seriously, he once said he was "much like Glenn Hughes"), but Turner tends to be an over-eager puppy and talks too much.