Depends on what you mean by "turned the corner." UT has had some pretty awful teams in the last 18 years and only won 2 games in the rivalry during that span. Furthermore, UT has lost some heartbreakers during that span in ways that makes one think there was a mental block with Tennessee (some would say "curse").
So in addressing those two dynamics, I think that A) UT isn't going to suck for awhile now that Heupel is in charge. I don't think it's a stretch to think that at this point; and B) Tennessee isn't going to have a mental block against Florida with Heupel in charge. That's just not in his culture. He instills confidence and aggression (kinda like Spurrier did).
And yes, Florida is going to get more talented, but so is Tennessee, especially on defense. Moreover, from a coaching/tactical standpoint, Tennessee will not be lacking as it has in the past.
So is UT going to own the series in the near future? I guess it's possible, but no one is predicting it. But I also think it would be a stretch to think Florida is going to keep dominating this series in the fashion it has. Maybe one team wins 6 of the next 10. Maybe it's Florida, maybe it's Tennessee...but if it's Florida it will be because a really good Florida team beat a really good Tennessee team 6 times out of 10. And in that sense, yes, Tennessee has turned the corner in this rivalry. If you're gonna beat Tennessee, it's gonna be because you're really good, not because Tennessee isn't good or has a mental block.