Originally posted by felixader:

I am pretty sure they weren't able to do that before (i hadn't played in a while before the last update) because I tended to use these tower as forward operating bases and protection from enemies like these. Additionally it was just fun to outsmart enemies via "civilization" so to speak and to fend of an attack from the ramparts.

And quite honestly, that a troll can just lay utter waste to these towers now literally within half a minute, kinda defeats not just using these towers but using stone as building material beyond the visuals.
For smaller enemies wood does just fine and for larger enemies wasting resources on stone buildings when they are this useless, well, it makes no sense.

EDIT: And it was also one of my main components how to defeat bosses. If the Troll is that strong then i am wondering what happened to the bosses. Basically i am mourning the potential death of my playstyle. :-/

1-2 starred trolls swinging a log are pretty hard on structures including stone.

However, as others have said and as folks have posted for a long time on the forums, you have to protect your structures with either high earthen walls moats or other such things.

Trolls main weakness is like with most mobs in the game, they're simply vertically challenged.

Also, I know you said you renovated a stone tower and I assume you mean that you repaired all the stones with the stone cutter station and built more stones? If not and you just simply renovated with pieces of wood, that structure easily would be destroyed because ruined towers' stone pieces vary from healthy to almost 1 shot from destruction really. But again you have to protect your structures with defenses.