Again, to be fair, the majority of the maps in question were mods made by the community.
Secondly, you pointed out you downloaded entire gigabytes worth of maps, this would probably deter most users with bad internet or such upon trying to download the game and finding it takes hours, assuming of course these maps were made default like one could suggest. If not, this assumes a player without RTB even finds the forums, which a fair amount of BL players don't even do.
Thirdly, I'm going to go on a limb and say the concept of Blockland isn't adventuring in maps, but building things with plastic bricks.
Lastly, many of these things you used to love doing can be replicated (albeit in a less beautiful environment approach) in current Blockland if you or someone else takes the time to just build another map.
Please don't interpret my post as rude or inflammatory, I'm just merely trying to suggest that maps aren't the be-all-end-all of Blockland's features.
On the flip side of that, I would love for maps to be reintroduced, but that's probably not going to realistically happen any time soon.