Buyers are all at different places in their expectations and perspectives. Those of us who frequent the old house forum would look at the unfinished room as a blank canvas in decent repair we could finish off to our heart's desire. It would only reinforce how much you have done to the other rooms.

Let's put it this way..........in most cases I don't think it would stop a sale in its tracks if the rest of the unit is as lovely as it sounds. It may make a difference on pricing because the prospective buyers would factor in completion costs. If they are realistic in their estimations to finish it, then it's six of one and half a dozen of the other. You either lose that amount in a potential sales price, or you finish it off and still lose that amount.

You know your audience better than we do. Are they all turn-key buyers?

This apartment would attract a turn key audience yes. However, there are people who buy turn-key in the complex and keep everything "as is" in the condition I purchased at with a paint job, if you know what I mean. (Run down but charming anyway?)

I am little worried that this one room is going to turn off the buyer that is turned on by the rest of the apartment.

There is one extreme example in my complex where the kitchen and bath were featured in a book, but there was a divorce before the renovation was complete. (That apartment is literally bipolar in appearance. and turns off both the turn keys and the renovators and its been on and off the market for years.

I don't think this bedroom is that bad, but I feel a qualitative difference. I may be more sensitized to it than most people.

As someone who overimproved (not historical) I understand see the hesitation to finish or not finish.

Here is what has to be done, then there is optional:
you have to fix all cracks so it looks good, and put a nice coat of paint on the walls. If there are really crappy closit doors that are out of place, you have to replace them. The fireplace has to be delt with, it either needs to be covered over, or broken through and finshed to some level of finish.

you don't need to make everything "perfect to the period" but it needs to be move in condition and nice. bland is ok, old, cracked, unfinshed,or partially exposed, it cannot be.

Granted you could put a for sale sign up tomororw, but you are really doing yourself a disservice to do 90% and leave 10% unfinished, it will cost you. However, unless you really have historical house snobs ( I mean in the nicest way) as a rule in your area, it doesn't have to be to the exacting detail that you went to in the other rooms, stock trim is probably fine.

Another problem with leaving it unfinished is that, especially in this economy, it gives the Buyers the impression that the seller is broke and unable to finish. This perception, real or not, will result the buyers in presenting lower offers than if it was finished.

You know, I think that is a very good point.