1.4.0 brought dramatic increases to personal survivability. While playing the Eternal Citadel, I found that most players could survive a 4 player spike for 10 seconds without a healer. However, most players could not survive a 5 player spike for 10 seconds. So my group started playing with only one healer, and it worked exceptionally well. Having 2 healers in party with one being a dps healer is much safer since the dps healer can rez without costing the group healing, but using only one healer worked out ok for us. I expect to see a lot more DPS Shamans and Archmages in groups.
Also I found that I could not get away with my typical glass cannon spec as a SM in EC after a few scenarios. A lot of players seem to have learned how to focus fire squishy tanks. I ended up switching my renown to Cleansing Wind 3, Reflexes 4 and Futile Strikes 3 and moving to 5 Defensive/4 Offensive Sovereign gear. I will play around with Trivial Blows 3 with a Liniment of Immutable Defiance and see how that works too. Glass cannon tanks will likely be viable in warband play only.
Mythic wanted to tone down the DPS tank. I think they did so with the scenario matchmaking system and the renown revamp. I just get wrecked way too fast to be useful to my group glass cannon in scenarios now. I still have my 2h and my Khaine spec since Nature's Blade is just awesome. Going from glass cannon to survivable cut my damage by one third. It does allow me to now take focus fire and Guard damage at the same time, which I just couldn't survive even with 2 healers on me glass cannon.