No, that would be just pointless. It would be much better if it was its own universe, just like D&D and MTG. While D&D is a roleplaying game and MTG is a trading card game, Chainmail would be a miniature wargame, simple as that. A newly invented version of Chainmail wouldn't be a set of rules for D&D miniatures, but a completely new game built from the ground up. Think of it as an American equivalent of Warhammer, but with not too many similarities.
The problem I see with that is that Chainmail, as a brand, is strongly linked to D&D. It would be risky for WotC to sever that link.
Chainmail, on its own, isn't as widely known as D&D and MTG are and a mini wargame not tied to D&D would likely fail. It's like [MENTION=6616]Maggan[/MENTION] said,
"They would basically disregard all things they are good at to try to compete in another field where they have little or no experience."
WotC doesn't have a good track record with minis.
I think Hasbro would have better luck marketing and selling a line of D&D-based toys than WotC would have with a new version of Chainmail.
The Sundered Empire, however, would be good as a board game in the same manner as
Conquest of Nerath. Plus, it is something that WotC has already committed to put on the market.
I'd like them to design similar board games for Planescape (i.e. The Blood Wars), Spelljammer (i.e. The Unhuman Wars), and Greyhawk (i.e. The Greyhawk Wars).
However, I'd still prefer WotC to concentrate on creating campaign settings and useful, fluff-driven supplements for D&D.