The grenadiers have 41 siege dmg every 3s, compared to 54 siege every 3s in The asian dynasties (TAD). They were not very popular in unpatched aoe 3 or in TAD even though their siege was more than 30% higher than it is now. That is why I think that their siege dmg should be restored to the TAD-value. Grenadiers should have 54 siege dmg.
Other units with high siege dmg are much more cost efficient. Pikes have 32 siege dmg for 80 resources, while grenadiers have 41 siege for 180 resources. So grenadiers have 28% more siege dmg for 125% more cost compared to pikemen. In terms of cost, grenadiers deal 43% less dmg per cost compared to pikemen. Compared to musketeers, they only do 13% more siege dmg per cost. In other words, they suck at dealing siege dmg.
I think that is terrible that grenadiers have been nerfed when they were barely used in TAD. By restoring the sige dmg of grenadiers to 54 siege, it would be a more balanced unit. Their dmg per cost would be 25% lower than pikemen and 50% higher than musketeers. That is more reasonable for a unit which is only good at sieging.