Undoubtedly Weber is going to get left behind in the modern pace of the NHL as he ages and his skating gets even worse (it's already bad). I want no part of that contract. Hell he is still on the IR...

Edit: Gardiner also gets a much larger contract i'm guessing.

I explained many times, as his Billus....this isn't how the salary cap works. The Leafs have high performance bonuses that must be paid and Horton contract has been included on the opening day roster in order to fit that years cap. So really, the cap probably doesn't work in 2018/19, and 2019/20. You really can't plop in a 2019/20 roster without considering when the performances are paid. Not only for the Leafs any team,
OK, the following is just my opinion, but Weber isn't the guy for the Leafs. The Leafs aren't going to be true contenders till 2019/20 at the earliest. In that year as you suggest there will be a multitude of potential UFA, Doughty, OEL, McDonagh, Karlsson maybe others. The Leafs can certainly wait to see their current young D develop before acquiring Weber. And Weber's contract is a detriment to any team holding it.
I can't see Weber being the panacea that will bring the Leafs instant success. He hasn't done in his prime with Nashville and Montreal, no one player is.
So IMO Weber's contract, the cap, and the Leafs time line makes me a Weber trade to the Leafs is poor choice.
If possible I would like to see Weber traded to another team besides the Leafs. You would think a player at Weber's stage in career might put a true contender team "over the top". But I think you would get the same feed back from fan bases of other teams regarding his contract. And ultimate question would be if Weber is that much of different maker, maybe Montreal should keep him. He has eight full years on his deal, surely the Habs could use Weber at some time if he such a difference maker.

Weber is on his way to being washed up, is too old, and that makes this a bad contract to take on.