Well, it could be changed to the arsenal which would make it less historically accurate. But really, is a late era building that bad, all the WWII Civs seem to do just fine with them. Either way don't worry about the effects, they are worth it
Edit: yeah I admit I play also with extended Eras and never get to the modern era (mostly due to crashes). But I don't see the point of picking a Civ with specials for a certain era and not playing in that era. When I play Stalin for instance I make sure I start at least in the Renaissance, besides you get the cavalry UU in the Industrial era, which is one era before the modern one, I don't really see the problem (not that we are not willing to change it though
).