Dev Question: Renaming "Vulnerable"
As you may know, monsters can sometimes "go vulnerable". The word "vulnerable" flashes over their head along with an icon and a particle. For the next few seconds, the monster is "vulnerable" and there are abilities and mods that do extra things to vulnerable targets.
When I'm looking at what changes are needed to combat, this mechanism stands out as being especially hard to figure out. It's actually super simple -- it's either on or off -- but players don't figure it out, sometimes even after playing for many hours.
We can add pop-up hints and stuff, but I think part of the problem is the name "vulnerable". It's very generic. "Vulnerable" can mean lots of things, such as being weak to a specific damage type. Players see "Vulnerable" over the monsters' head and go "huh, that's good... I guess." They see that abilities do extra damage "to vulnerable targets" but that doesn't really click with the word "Vulnerable" over monsters' heads.
So I'm thinking of renaming it to something else. Right now I like "Off-Guard". You'll see "Off-Guard" pop up over monsters, and you'll see some abilities do more damage to Off-Guard targets, and I think that'll be a little easier to figure out. But before I go changing the text in a thousand places I figured I'd see if you have other suggestions!
Expressing weakness as a concept
You used the simplest term in asking us this question--"weak." Whether players would connect that word with the skills that work best when it shows up is another issue. In the first days of playing Gorgon, I'm pretty sure someone pointed out that I had a sword skill that worked best on vulnerable targets or I wouldn't have noticed right away with so many other things to learn starting out.
Weak is probably the best answer, but it's linguistically not very exciting.
Maybe "easy," "open," "frail," or "soft" could work. Very short words that are more common could breach linguistic barriers, since English isn't always the primary language for players.
A couple other more distinctive words could be along the lines of "wimpy," "jinxed," "worried," or "spooked."
The flashing sword as an icon never seemed to fit with vulnerable. However, the word you use and the symbol shown need to match! Maybe a picture of a ghost with the word "spooked."
I'm still thinking and will add additional brainstorming if something good comes up.