DLC doesn't have to be a dirty word in itself. For starters, it can be free (as it was in Unreal Tournament which, as far as I know, pioneered the concept). And it can greatly expand the lifetime of the game; I wouldn't be playing TF2, Civ 5, Skyrim or Dawn of War 2 without their DLC.
The trick is for it to be material that's developed after release, so it's not a left-off-the-disc buyer-screwing, and that it's priced right - for £10 it needs to be a full-on expansion pack (as in Civ), not a few maps and a gametype. Epic would give that shit away for free.
:edit: Gah, so many ninjas on these boards.
:Re-edit: Also, in my opinion, multiplayer maps and gametypes make for bad premium DLC as they split the community. Any extra online content needs to be usable in matches with non-buyers, such as additional characters or weapon customisations. Either way, once the multiplayer scene dies down, very few are likely to buy it (which may have happened with AvP3's DLC, I don't know how well that sold).
