We want siege engines!
We want siege engines!
...
These siege engines are bad!
These siege engines are bad!
Whether or not these engines are perfectly balanced, they are a step in the right direction.
I think that the suspension repair will be good, although flax is already a pretty popular trade good. What if you need more glue to fix it, and it takes time to cure in proportion to the amount of damage done to it? Then you can inch it closer to the wall, pausing occasionally to repair the ram, or just charge it up against it and try to repair it all at once, protecting it while it dries?
Maybe Capped Rams that use metal and are somewhat better, and log rams that are too weak to do much to brick, but are useful for palisades and small cabins?