I think Sazed trying to moderate the influence of Ruin in his "works" is strictly time limited. Purely because he can't keep it up forever.
If he's suppressing Hemalurgy, for example, that's an effort of will against the Intent and it's going to push back.
Ideally he needs to find a suitable outlet for the requirements of holding Ruin, I think.
Having a lowercase-A avatar like Wax allows him to act in the world but by the end of TLM I think Wax is an even better representation for Harmony given that he's spiked.