I don't think that'd ever be the case- they still do have a fair amount of space, especially if they go up and like, hover over the sea. I don't think they'd go underseas but for an underwater let's play (removing water source blocks is a ♥♥♥♥♥). And they know what Xs would work- nothing where so much was covered in the first run (Hit List, Shopping List) and nothing that sucked (Creeper Soccer, I Spy unless modified). I think CTT will always be fun with minor modifications each time, Lava Wall could use another run, Snowbound might be cool still. If they really really need space or resources I'm sure everyone could be let loose in another world. :P
I think Geoff has said he's got planned through episode 123 now? Things coming up could include Galacticraft Mars, Ice Cube, King Gavin, King After Gavin, Monopoly part 2-?, Lava Wall X, Snowbound X, Cloud Down X, Mega Dig, mysterious underwater let's play, TUNNEL.... am I forgetting things? I'm sure there's new ideas gonna be going through as well but that's already a lot of fun stuff. :D
I dunno! I'm... gonna wait until Ashley tells me on the Know lol
why bother looking up news