Yes, but not as ones you'd find in the LFD.
I'd rather have long AND difficult dungeons, ones that you might not expect to finish upon entering (challenge mode difficulty or harder), and have them reward something decent, either LFR gear or something different.
I'd love challenging 5mans to come back without that challenge being tied to a time trial, ones that fit into the gearing system. But they'd need to be separate from the LFD tool.
Similarly, I'd like to see some of the larger BGs like AV / IOC be taken out of the normal PVP queue and made into their own, longer BG things. Can add instanced versions of wintergrasp and tol'barad to it, make it it's own thing instead of having a queue that could get you a 10min WSG, or a 40min AV.