So one of the recent Blizzard posts focused on incorporation of meaningful LFR gear into challenging 5 man dungeons. It sparked an idea that could potentially capture 3 important issues that seem to come up:
1) Lack of meaningful 5 man progression
2) Lack of open, sprawling dungeons
3) Griefing and poor performance in large scale LFR
The idea is to release one or two 5 man dungeons with each major raid (or on the in-between patches) that have a 10 man instance capacity. The idea is that you release a UBRS/LBRS style dungeon that is tuned to be quite challenging for a 5 man group. When completed as a 5 man group, additional rewards such as mounts, currency, higher ilevel, etc. is obtained. But, when a group is formed using the new LFG tool, up to 10 people may enter the instance. The catch is, though, that the dungeon stays exactly the same as the 5 man version, except the "LFR" group members can now bring in extra heals, tanks, and dps to make mechanics easier on the 5 man fights. You can now award meaningful gear in a smaller setting to people who like the convenience of LFR but need a smaller setting to reduce the problems of 25 man.
The actual content of the dungeon would introduce an event related to the current end boss (see HoR and escape from the lich king), so that all would be able to see the final boss, even in a small setting. The event would be very challenging for a pre made 5 man group, but much easier for a group that can bring in an extra tank, or an extra dispell, or extra dps to ease certain mechanics. As for enrage timers and dps races, it would be assumed that 3 dps in a premade group would do similar amounts to 5-7 random dps in an LFG finder team. The larger dungeons would have 5-8 encounters and would likely be tuned as 5-8 minute fights.
I personally would find this extremely attractive as a casual player as I could have a meaningful, small scale catch up that I could do with my friends. If I get back after a Hiatus and it's the 3rd raid tier of WoD, I could progress through the first open 5 mans and have a quick taste of the previous tiers.