A couple of things:
Weise's back-to-back career years have come while getting significant offensive opportunities, and despite that, he hasn't really produced much like a reliable top 6 forward. Also, I found he's been quite lucky this season in terms of goals. As such, I'm still very skeptical of his goal scoring prowess. Something like three of his 14 goals have come from him trying to make a pass into the slot area and getting the luckiest of redirections. I mean good for him, but a lot of top 6 minutes and PP time have been invested in his career season, and it still is underwhelming imo...esp considering he had like 8 goals in his first 18 games.
Also, he's bound to get way too much money for a tweener. Given that the cap is going down, you can't get invest too many resources in what is ultimately a replaceable player imo.
Lastly, and most importantly, I wouldn't bring him back so long as Therrien is behind the bunch. The result is an over-usage of Weise at the expense of other players, and I just don't want another DD on our hands. it's not worth it.