The Leafs would benefit from any top 4 caliber defensemen rn

Correct Hanifin isn't a 6 million defenseman, he's comparable to Morgan Rielly. Hanifin has been better defensively and just like Rielly though not a shrinking violet he isn't as physical as you'd like him to be considering his size. Hard to say about offensively unless/until they play on the same team.

It's likely the only significant difference between the two has been systems and coaching. Put them on the same team and they're probably about equal across the board. Big skilled defensemen who could be elite / near elite if they used their size better to be more physical, hit harder, pushback more and get into the occasional fight. As it is now neither one throws their weight around or intimidates anyone, nobody is worried about going into the corner with them.

I am ok with the Leafs not improving areas of weakness - this works for the entire Eastern conference lol.

He's not comparable to Rielly in the sense that he can't carry the workload that Rielly carries...

But he'd be a welcomed addition to the blue line and would help a lot

Sure he can. He plays big minutes in all situations.

But not 5th in the league in ice time minutes

Again that probably has more to do with coaching and systems than anything. Well that and the fact the Leafs don't have anyone else as good as Hanifin or Reilly or even close. Calgary on the other hand has Andersson, Weegar and Tanev.

No, it has to do more with the Leafs having nobody else who can carry Rielly minutes...

That's why Hanifin would help so much...

Rielly would go from 25+ minutes to 22-23 minutes which will help him a lot

And Hanifin sometimes plays 25+ minutes too. The difference is he doesn't have to do it all the time because the Flames have multiple good defensemen who can play big minutes. Andersson, Hanifin, Weegar and Tanev all can and have done it.

Overall, Leafs can benefit from Hanifin

Overpay from the Leafs side of things. Take out Hildeby and its a deal. If you want him, Hannifin needs to come with a friendly contract already signed. Otherwise its just throwing assets away on an overpriced rental.