Late game warfare in CiV seems to be a very subjective issue. I for one like modern wars in CiV more than I did in Civ4. Not only artillery, but all these fast moving units... don't you enjoy your sorrow regarding your elite artillery when you see the AI's gunships flying around?
I'm frequently close to panic.
And yes, double shooting long range artillery is sort of imbalanced. But then, you had to work for it and may take it as your well deserved gratification. Additionally not *all* of your artillery will be experienced veterans. And siege artillery against a fortified, city-defending artillery is still tricky.
Nevertheless, AI makes good enough use of their own artillery and I like, how I'm forced to hunt them down with my bombers and fighters.
But I have to admit, that there are some fascinating features less present in lategame:
One was already mentioned: there are less UUs than in early game.
Second, there are less modern world wonders to hunt for.
Third and maybe most important: The whole world is already known, all cities settled, all luxuries claimed. The excitement of the discovery of an unknown world is lost.
Regarding the first two points, there can be relief (at least theoretically). The third point is intrinsic to civ games and we have to live with it...