In fact sitting in a top-notch 25 guild right now, maining a RestoDruid, i concluded the same issues that Myrrar already mentioned. In terms of hardcore progression RestoDruids just can't get on par with other healing classes, the main Problem being that Fights are mostly seriously underhealed. Concerning pure HPS values while underhealing a perfectly played Druid is not able to outheal Monks, Shamans and Discipline Priests right now (if played equally and referring to MV only for now) and although he doesn't drop that far behind there's a small gap noticable. Still the real problem is rooted elsewhere...
RestoDruid playstyle supports Raidsustain more than anything - sadly, playing with 1-3 Healers less than the fight is intended for the capability of sustained Heal is not what your Raid longs for. It's more like other Healers right now can solve the job of a Druid as well for EVERY damn case, while Druids aren't able to do theirs. Like i already mentioned Druids fall behind in HPS a little bit for many cases - even if its mostly like a few k HPS only. Still Druids have the weakest Burstheal capacity and NO RAIDCDs that aren't directly reflected in HPS (which is still "low").
Thus - with Monks being introduced to the game - Druids completely lost their edge because with Healergearing being a big issue in Progression Guilds as well nobody wouldn't gear the most valueable character IF an item happens to be considered Healerloot in the first place. Druid (/ Monk) right now is the only healing class competing in Gear with more than 1 respective hybrid DD-Spec for Armor-pieces.
We have a raid CD - Ironbark.
Yes, but ironbark is so weak it's like saying pw:shield is a CD. It's just not a very strong or impressive CD compared to the multiple every other class has.
We used to have tranq which was unique and powerful so some fights it bumped us into a raid spot. Tranq is a joke now on it's own, and compared to others CDs.
I know of quite a few R-Druids in top guilds.. You must not have looked very hard >.<
R-Druid 4life
The dream being resto died a long time ago for me. Blizz completely fukked them in Cata, and I haven't looked back since (quit for a bit, and then in MoP switched to Guardian). Resto was so fun in WoTLK, wish they would revert it back to the way it was, would switch in a heartbeat.
Zen Meditation - Spell - Wowhead
It was much stronger in the beta. Right now it's nothing special.