From what I've seen, the Wu Jen is generally considered to be High T2, rather than T1.

I'm not convinced the Druid's spell list is significantly better than the Wu Jen's.

If the Wu Jen is T2, I think there's quite a strong argument that the Shapeshift Variant Druid is also T2. Wildshape and Animal Companion are not just "candy," they are class features that are stronger than some entire classes. IMHO, it's only because of them that the normal Druid is undebateably T1.

Of course the Tiers can be defined in a few different ways. T1 has traditionally meant the "Big Six" (or Five if the StP Erudite isn't counted as a class), but if you want to drop that tradition and argue that Wu Jen, Spirit Shaman, and Shapeshift Druid are all T1 in spite of not being "Big Six," that makes sense too.