The large scale shinra tensei is only good against people who he can easily beat, or when he has a teammate to hold the opponent down. Otherwise its a take too long, and someone with Hashirama's experience and fighting prowess it'd be too easy to take him out or disturb him.. And plus he has to get in the air first.
And what is he gonna tear from the buddha? just 1 arm?

<< Thats pretty much all chibaku tensei has shown the ability to do . Also, Mokuton wood is different for specific jutsus. For example the one used in the forest is "weaker" than the one used for the statues.
@Bold, You are making it seem like Hashirama just sits there and watches it.....
1. Lets look at the main stats from what they have shown:
- Ninjutsu= Hashirama > Nagato
- Genjutsu = Hshirama > Nagato
- Fuinjutsu = Hashirama > Nagato
- Experience = Hashirama > Nagato
- Taijutsu = Hashirama > Nagato
- Kenjutsu = Hashirama> nagato
- Strength = Hashirama > Nagato
- Speed = Hashirama > Nagato
- Reactions = Hashirama > Nagato
Nagato isn't superior in any of those categories that are used in a naruto fight.
2. Wood clone by itself can destroy Nagato, without Hashirama having to even mess with Nagato. Wood clones possessed enough power to lead a Juubi's TBB to the ocean via Jukai kouton... Then you have the mayfly ability, allowing the wood clones to merge into the ground or any other enviorment. And not only that Hashirama can change the power between all of his clones.. Good luck to Nagato.... And whats more annoying for him is the fact he won't know who the real Hashirama is.
3. Chibaku tensei is too easy to counter with mokuton
4. Chou shinra tensei only gets him killed.
5. Hashirama can also lock down Nagato via Wood dragon.