I don't see why they can't just code them back in to work with the shadows. I mean, sure it would be work, but what isn't?
I know nothing of the coding behind making Blockland, nor of how Maps worked or what exact problems they caused in coding.
But I can only assume that even if Maps were capable of being re-implemented in some way, shape or form that didn't break other functions or restrict further development, it's just not a high priority for Badspot.
It's not a necessity for the game, and there are other functions/aspects of the game that could do with additional work on them and have been in need of a touch-up for some time.
By all means, hold hope that perhaps they can be reimplemented at some time, hopefully in a better quality than we ever had them before.
But there's no point holding your breathe over it or focussing whole-heartedly about it. If it happens, it happens.
There are plenty of other things to look forward to first.