It won't hurt anything, as long as you remember the extra dilution, but you're likely to find it relatively difficult to get everything to fully dissolve (prolonged stirring in a hot water bath will eventually make it go, though). The issue is that, at double strength, ID-11 will be putting around 200 g/L of sulfite into the solution, which is pretty close to saturation -- I failed, a while back, to get 225 g/L of sulfite to dissolve with nothing else involved (making a stock solution of sulfite), and had to back off to 200 g/L, though the official saturation point is variously reported as up to 250+ g/L.
Worse, if the sulfite is that close to saturation, you might find the metol doesn't completely dissolve (it's notoriously hard to dissolve in strong sulfite solutions -- in mixing D-76 from raw chemicals, you'd normally add only a little of the sulfite, then the metol, then the rest of the sulfite to get around this), which could lead to a situation where the developer is weaker than it should be or changes strength as it stands (and the metol slowly dissolves with standing).
What I'd suggest is to go ahead and try it -- and if it doesn't fully dissolve, get a 5 liter container, pour your existing mixture into it, wash down the smaller container with some of the (warmed) water you'll be adding, and remix to the 5 liter volume. As long as you pick up all the solids when remixing and they finally do fully dissolve, no harm will be done.