There's certainly an advantage to having everything enumerated in one place, but I think you'll find that the Transformation domain kicks in pretty hard if you research a bit.
Transformation domain gives you Alter Self at level 3. Alter Self gives you
fly/swim/burrow as well as natural armor up to +8 and claw/claw/bite w/multiattack. Clerics of course can get it 24/7 at level 3 via DMM[Persist] which has many other applications as well. Here's a tradeoff table:
Code:
Alter Self Wildshape
+L3 -L6 (to cast spells)
+keep gear -lose gear
-keep physical +new physical stats
-no Ex attacks +gain Ex attacks
+no familiarity -requires familiarity
Both have:
+effectively all day (via DMM persist or just hours available)
-requires feat to use fully (Natural spell, or a partial share of DMM[Persist])
+good utility
+good combat
At level 9 the cleric then gets Polymorph which is generally far more adaptable than Wild Shape. And a level 15, there is Polymorph Any Object which is broken-good. At level 17 the Transformation cleric gets Shapechange. It's not until level 18 that the spontaneous druid also gets Shapechange.
Overall, the spontaneous druid has some advantage L6-L8, while the transformation cleric has an edge L3-L5 and L9-L17.