Well it took seven years to code all of Blockland, and to go to a new engine it would all have to be re-coded from scratch... So take your pick, is it that hard?
ehh
a lot of the time literally went into engine changes, I think.
A Blockland remake in another engine would certainly be a challenge, but not a 7-year challenge. As Fox said, the brick and event systems (events need a huge redo anyway) are pretty much all you need to remake. The biggest problem is add-ons, which will be totally incompatible. Blockland is a fairly basic game, when it really comes down to it. The only thing that separates GMod from Blockland is the bricks, minigames, and community. At this point, I think Blockland, development-wise, is running out of steam, and I understand that after 7 years, one project can really burn you out. I think Badspot should just abandon ship and create a sequel in a new, better engine and with a nicer scripting language, but it's not up to me.