I was at first thinking "Huh?" when I saw the topic, seeing as the general consensus seems to be that Knights of the Nine is the best Oblivion DLC (Shivering Isles doesn't count since it's an expansion.) but I see you just mean price, in which case, I can't comment on that because I got Knights of the Nine from the GOTY addition, which I'd say seems pretty reasonable considering what it offers, as an individual plugins, it definitely seems to me tha Knights of the Nine is the best Oblivion DLC. I think with the previous plugins, Bethesda was still trying to find the direction they wanted to take with the game's DLC, hence why we got Horse Armor. If you look at the Fallout 3 DLC, while we can certainly debate about the quality of individual plugins, even Operation Anchorage was leagues beyond Horse Armor in terms of the content it offers. While I'd much rather have even just one full scale expansion than lots of DLC, if I don't get to choose, if Bethesda insists on doing DLC only and not expansions, then I'd say go with more ones like Knights of the Nine and the Fallout 3 DLC, as in, adding a new quest or questline, new items, possibly new locations to explore, rather than just releasing a new suit of armor and expecting us to pay real money for it or some other ripoff like that.
I would rather them come out with 2 or 3 really big expansions than a whole bunch of DLC any day.
My thoughts as well, actually. But it seems that Bethesda has chosen otherwise, I guess there's not much we can do about it if that's the direction they've chosen.