Well, I understand the argument for terraforming, and I’d bet good money we will terraform it long before disassembly, but I’m more of an O’Neil Cylinder / Dyson Swarm kind of guy. I prefer the idea of overwhelming surface area via orbital habitats rather than colonizing gravity wells. I also don’t trust Venus not to catastrophically resurface itself and refill the atmosphere with CO2 and sulphuric acid in a mass volcanic event.

Furthermore, far too soon the Sun will expand into a red giant and devour Mercury, Venus, and likely Earth as well. If it’s possible to employ a Dyson Swarm to lift material from its surface to reduce its mass, then it may be feasible to prevent or mitigate the red giant phase to preserve Earth and extend its habitability, perhaps indefinitely. If preserving the birthplace of known life seems more important than building a copy in a more precarious orbit, then we ought to sacrifice that copy to expand the Dyson Swarm. Mercury first though. We’ve got time. Mars can probably go too.

Considering the eons involved with stripping both inward planets down to the last bucketful though, I’m certainly in favor of a few millennia to fully explore and research them both beforehand.