If Blockland were to go to a new engine it would be moved to Torque 3D since its now free, open source, and Blocklands current engine is from Torque. It would be the easiest to port and Badspot could modify it more since its open source.
Edit: Why is it that whenever someone suggest a game engine that blockland should be ported on you guys think blockland will look like a game that uses it such as Source and L4D2. This is the same with the other post about being on the cry engine or whatever it's called. Blockland can have the same graphics, and since they won't be as demanding as the gsme engine supports we would be able to have more of the same kinda of graphics.