I live in a very small open concept condo and I decided to arrange my furniture so I always have a 3 feet wide path to move around, and I can say it is a confortable width (for one person). But for two people, maybe less than 2x3 feet is ok, as they make double french doors starting at 4 feet wide... Suggestion : put some masking tape marks on the floor and try visualizing !

Well, for lack of a better idea, since you find it a drafty little space. I'm assuming the draft comes in on the right? Most of the necessities in the area are located of the left side; i.e. vent, thermostat, light switch etc. What I would do I think is caulk up the drafty spots, maybe even add sized poster board wrapped in batting I covered in a gorgeous fuscia with diagonal grosgrain ribbons every which way covered with a heavy velvet to be attached to the area above & below the window. (Of course remove the drapes that are hanging in there). This for the purpose of using it as a pin-it board for notes. Attach a table height board covered in felt to carry across the full width of the little room. Leaving just enough space for a comfortable little antique desk chair. Paint the back wall a bright cobalt blue, paint the ceiling a silvery pearlescent white. Find a way to attach a clip-on task lamp. And stretch a heavy duty enough wire across the top of the opening and complete it with a heavy doubled velvet drape with a drooping valance. Place a swag with fringe & jewels on it to be closed when not in use. Voila intrigue is yours!

Some inspiration, the last pic is clever with the bookcase, you would have a lip on the shelves to stop books falling off every time you open the door, but it sure serves two purposes

Here's a couple of ideas that work really well as alternatives to a walk in pantry. They integrate into your wall cabinetry, allowing you to keep central spaces open and free flowing. Using drawers to create a pantry as Esselai suggests. Check out how Harn Triomax soft close drawers are used in just this way. Availble in classic white or metallic grey. Two front to back depth options - 500mm and 5500mm. And 8 drawer width options from 450mm to 1200mm. Alternatively, there are a number of quality pull out pantry options in the German designed and made Vauth-Sagel range. Some are installed with fixed fronts to match your cabinetry, and others are installed behind hinged doors. See below (from top to bottom) the VSA model, DUSA model and HSA model. These all come in a variety of width options and specs, from chromed wire shelves to sold bases with glass panelling.