Did you only play the game recently? If so, then as Stabbey pointed out, what you played is the result of countless of balance changes. The hypothetical question is, if you were to play the release version of DOS2, would you say that it has better balance than the current version of DOS2DE?
There's the good kind of imbalances and the bad kind of imbalances. The bad ones *need* to be fixed - that's part of improving the game. I don't suppose you know what Bone Widow was like before they nerfed it?
I don't think you have to worry about the game running out of imbalanced stuff though. There's a thread around here somewhere that lists a number of things considered "broken" in DOS2. I haven't kept myself up to date with all the DE changes for some time, but I rather doubt they have "fixed" every single one of those.
Unfortunately, the problem is complicated by that the freedom to flee combat and return means that buffing Assassinate's in-combat effectiveness will also buff it's out-of-combat effectiveness and allow it to be exploited by running away while the rest of the party is in combat, coming back in Sneak mode, then Assassinating again once the cooldown is off. This skill is balanced around the possibility of it being used outside of combat.
Not to start an off-topic mechanic argument, but would anyone bother to use Assassinate in such a way? That's a lot of extra work - flee, return from waypoint, sneak, wait for cooldown - just to squeeze out a tiny bit of extra damage. If you already resort to the "flee / return / land free hits / repeat" strat, there are plenty of skills that are WAY better. In fact, whether it is in combat or out of combat, there's just no reason to use this skill instead of Ballistic Shot. The only situation in which a skill like this would actually be useful is when you really need to finish off an enemy when you have 3 AP left, and that 15% extra damage is just enough for you to pull that off. But then, you could also just pop a potion of Finesse or cast Peace of Mind on yourself, then basic attack, and would achieve the same thing.
