As a druid tank I've tanked almost every heroic and 10 & 25 man Naxx with no problems. So I'd say no we aren't becoming obsolete and with the new Savage Defense ability coming soon we'll be even better!!
Savage Defense – this is a new passive ability. When a druid in Dire Bear form deals a melee critical strike, the druid gains a damage shield equal to 25% of their attack power. The next hit completely removes the shield regardless of how much damage was done.
