Even with new rules of transform, the cost is 0 so it gets hit by repeal, among most other bouncers. For mud I only like it against oath, where you can have extra spirits, and this creature owns griselbrand.
Against mud it can be metamorphed/duplicanted, and you are losing 5 creatures in the process (and good luck playing

+ tapping the land against mana denial strategies and without MWS support)
Against quick aggro it probably arrives late.
Against control you should be fine with 5 creatures, you don't need this. And if you have 5 free mana, to create tokens, play something else.
5 mana to create a token is too much, and having to sacrifice 5 creatures is also a whole world. This is like a semi dark depths (not really comparable, but has similarities), which sees little play despite being probably better.