druid/war and druid/lock ARE indeed awesome, but those are resto druids, not feral druids, and they win via attrition and control, something feral druids most definetely do NOT excel at.
ive seen ferals do well in 5v5 and 3v3, but a druids greatest contribution will be from the resto tree. as long as you dont have any problems with hanging around the 1800's for the most part, you should be fine. serious 2k+ rated druids arent feral tho, the spec just doesnt provide the needed advantages.
and yes, maybe someone somewhere will find a class combo that works great with feral at the 2k+ level, but the fact remains that in almost any given situation a resto druid will outperform a feral druid in terms of arena viability.