Guild Wars 2

I think the cannon siege addition is great.
But perhaps to unlock the full range and skills on the cannon, we should restrict it to cannon mastery.
The more points you put into the mastery, the more skills you can use on the cannon and the further and larger radius you can hit.
Similar to most of the other siege in the game right now where you need to put mastery skills in to unlock its full potential.

Also these mobile cannons should not be allowed to hit through gates or over walls.
I don’t know if this is doable, but if someone was allowed to build a cannon on an adjacent hill overlooking a tower or keep, he could potentially destroy all the defensive siege in there.

and give mobile cannons a decay timer if there isn’t currently.

If the above could be implemented, I think it will be great to have the cannons made permanent!