Last time I saw him live, Wolanin was the guy that really impressed me the most over guys with high end skill like Batherson and Brown. You could clearly see that he had that natural ability to create scoring chances all over the place in many kind of ways.
The reason why he is so "old" is that he was picked in the 4th round as an overager in 2015, so he was a "late bloomer" as he transitioned from forward to defense in 2014 (IIRC). He also stayed in college until he was 23, then played 10 games with the Sens as he was already close to NHL ready. The following year, he spent almost 50/50 in the AHL and NHL (looked really good in the AHL and was better and better every game in the NHL). He was going to be a full time NHL player this season and would have been one of the best players on the team.
Wideman was a decent player (albeit a bit undersized and weak defensively) but was really not the same after his injury, that's why he had such a short NHL career. MA Bergeron was a pure offensive weapon, one of the best shots in the league and a PP specialist but he couldn't play defense so he had a hard time staying in the line-up all the time (injuries too) and had to be sheltered. Still 490 NHL games and 235 pts, which is very good for a D-man.
All that being said, I believe Wolanin is in a completely different tier than those players. If his injury didn't affect his mobility, I see him being a NHL regular for at least 7-8 years. He's quality