I think I-70 should be extended southeast along 695 and 97 to Annapolis, then (granted, this part is purely hypothetical) go over the bridge and follow a new/upgraded 50 freeway to Ocean City. At least, that's a fantasy of mine. It would eliminate 97, which is wasted on that short stretch of freeway, and make 70 a bit more useful.
I-95 could mostly be completed through DC thanks to the revamp of the 695/295 interchange. All that would be needed would be a couple of higher powered ramps at the 95/495/BW Parkway interchange (and turning the parkway over to SHA, of course). Not that I expect that to happen, but its another fantasy of mine. I would still sign the beltway as being the way for thru traffic to go (Richmond/Baltimore control cities, with I-95 going inside the beltway signed exclusively for Washington). This would have the advantage of eliminating DC 295 and I-695 in DC, with I-395 relegated to the center leg.