I might be a little late to the party - over the past month, RL has kind of gotten in the way of following Skyrim news much, or even playing it much. Anyhow, did some searching to see if any new Skyrim DLC had been announced, and found this:
http://www.ign.com/articles/2013/04/15/no-further-skyrim-dlc-planned-team-moving-on
I suppose I'm not too surprise - it has been almost 2 years since the release of Skyrim, but it seems like most of their previous games got more than 3 DLC packs. I suppose, to be fair, Dawnguard and Dragonborn were both pretty substantial DLCs. Definitely got our money's worth with them.
Anyhow, Thank you Bethesda, for a great game and a couple of amazing add-ons. I do wish you'd consider making one or two more DLCs, but I also realize that at a certain point, you've got to move designers, developers, artists, QA, and other staff resources on to other projects in the Pipeline.
Well, there's still about a thousand third-party mods I haven't tried yet (and probably another thousand will be created over the next 2 or 3 years).