Of course maryland wouldn't want d.c. back. Maryland being one of the bluest states in the country would want to see 2 new Senators as well, but, and I don't know, but, has anyone asked them? Politics aside, I can't see any state refusing to acquire more land.
There is a constitutional argument here though. The constitution spells out the cession of land for the purpose of being the seat of government, not for the purpose of creating a state. So, what about the people in DC, well, it's not like one day they had representation, and then it was just ripped out from under them. They knew when moving into the state that they would not have proper representation. Sure, that doesn't solve the problem, they still need to be represented.
Granted, I'm fairly positive if D.C. trended red, that this topic wouldn't even be being discussed.
Also, there are many residents of DC who also have residency in other states. How many people are living in DC, and are actual residents of DC? There are people who live in DC that vote in other states.
Also, from what I've seen, their plan is to basically cut out all of the federal buildings and call that "DC" and then all the rest becomes a new state. OK, so...what if government needs to build a new building? Where do they get the land for that? Is it pretty much just a "demolish the old one and build a new one in its place"?. Where do the people that are currently in that office work if they have no building? What if the government needs to build an entirely new construction? Are we going to get into a situation where the new state and federal government pass land back and forth as needed?
Maybe the government doesn't need any expansion and this is all doesn't matter?