You have apparently never seen good tactics in use

Just some strange shade of almost-good-tactics..lol (no worries james, I'm not being insulting here, or at least not trying to be, but it happened, and it can again. There are lots of threads about such things on here, I think there was even something like it in the wotc stuff on their board)
kobolds are mean creatures, but many can be when used to their full extent.
Neither here nor there though. The spiked chain is generally less useful than most of the other weapons out there that are more 'common'. At least in pieces, some in nearly every way.
You talked about vs several opponents and I said that that situation could be modified by just about anything. And it can be. It doesnt say much either way for or against in the case of the spiked chain.
It has its uses, it has its weaknesses, it has its strengths. Overall it is a very interesting weapon, somewhat unrealistic, but hardly overpowered. In fact I'll argue that most of the time it is underpowered. In the few ways which it is good it is pretty good indeed, but lots of other weapons could do the same thing, for less expense.