He reminds me a bit more of Nolan Ryan in that he can tolerate the walks because his raw stuff produces weak contact and a low BAA. Don't get me wrong, he's not in the Ryan strata at this point (and probably never will be), but Snell's stuff is top-drawer.
From time-to-time, I still have trouble figuring out how Glavine was as successful as he was given that he didn't have a "put 'em away" fastball that could tie hitters up inside. He did command the outer half as good as any pitcher I've ever watched and could hit that baseball-sized box in the lower left of the RHH strike zone consistently. Add to that he was an absolutely fearless competitor and you've got something.
Glavine is a classic tale of what you can do when you have elite command and at least 2 plus pitches (his change being truly elite). He probably wouldn't be as successful in this era due to pitchers not getting that wide of a zone anymore