Ottawa already has their RHD in place with Gudbranson and Zaitsev. They need space for Branstrom to grow into too. They are shallow on the left side though which you are taking away from to fix Buffalo's need. Ottawa won't be taking Risto off your hands for a price like that.

Zaitsev, Brown, Gudbranson, and Jaros? Id like to think teams would rather have Risto than any of those players. Can quarterback the PP and put up 40+ points a year that is not a high price. Still only 26

and now look at their left side who you are taking from.

Its like asking Buffalo to trade McCabe for another right handed defenseman.

I've been intrigued by Ristolainen, and if he plays the left side very often, so I've been watching videos of games with him recently, and the same thought comes to mind over and over, what the hell is he doing?? Why is he doing the same idiotic risk over and over?

He keeps pinching in about 1/3 way into the offence zone along the boards, to block the puck from exiting the zone, but there's an opposing player there as well, and at least one other behind him. It looks like he's trying to make a hit and block at the same time. Even if it works, it's a very risky move, and I kept seeing it against different teams, each time like he's trying to make a hit, and letting the puck get behind him.
This is a play that's done countless times a game, shooting the puck around the boards to get it out.

Watch these, pause them at 31 seconds in and 30 seconds in

https://youtu.be/zuL7X6sabwQ?t=22
https://youtu.be/fFSaKBMoMBQ?t=30

Or chasing forwards away from the goal in his own zone, getting drawn out.

He has real defensive issues. I've read up on Ristolainen, and the comments are just, defensive issues, without specifics. Difficulties exiting the zone with the puck has been the only specific issue I've read.

His coach needs to sit his ass down and tell him, do that again, and next time you do it, you sit, and each time you do it, you sit. If you don't want to play smart, then you don't play.

That's a really good Calgary trade. I think Calgary would have interest in it too. Sign me up

I know he will often go for the hit, but those are not great examples.
In the first one he was actually pinching and the second he played the body and not the puck.
I the first the pinch did not work, in the second he had a forward in position to allow him to play the body.
You will need to find better examples than those.

I understand your point, and about pinching, it's that the opposing forwards are either already behind him, or facing him where they have the advantage in heading up ice quicker. It's already a risky play, these both failed which happens, but they failed with the other team with a definite advantage. Forwards love rushing up ice against other forwards instead of defencemen. Neither resulted in a goal against, but that doesn't mean it was well advised.

When to pinch is an important part of being a good defenceman. Maybe I'm just too old school with my, never let the forwards get behind you, thinking.