Westy, I hope by "theme" restaurant, you don't mean TGI Fridays.
I could totally see Gordan Ramsey setting up shop in this space. Something like
Maze at the London Hotel in NYC (with an appropriately hard-modern decor) would rock.
No NO A Million Billion -- well maybe even Trillion times NO
By theme I mean something locally inspired with a range of dining options:
1) start outside on a broad plaza -- perfect for a late spring, summer, fall foliage cafe experience -- perhaps with alfresco cooking on a grill
2) perhaps a summer tent for a beer garden type environment
2a) perhaps a heated tent for some Holiday Cheer
3) Big Glass windows -- perfect for seeing and being seen the entire year
4) indoors some more colonial theme -- big Brick fire place for those winter afternoon / evenings when a mug of hot mulled cider is just the ticket
5) further indoors some more intimate fancier place with the 19th Century Brahmin feel of the old banks and trading houses -- wine bar and perhaps cognac and scotch
6) Upstairs some state of the art media rooms, sports? and private dining -- modern late 20 / early 21st century
7) Heck while we are at it -- perhaps a secluded small bookshop where you could curl up with your late or wine and browse some books
8) throw in some meeting rooms for lectures
9) lots of graphics how the Summer, Winter, Washington School St. area has evolved over 4 centuries
10) a place for tourists, suburbanites, downtown workers, and locals to have fun with good food and drink
Something to that effect