So as we all know right now, Thunder is a tad bit too powerful. In my mind it is not because of the effects, it is because the effects seem unavoidable at times. I came up with an idea that would change the way to encounter Thunder, where he is approached differently to fragger. A lot of people want cooking, but I like interesting gameplay, so fragger and Thunder having the same counter is a tad bit boring imo.
-Increase CD to 18 secs
-Increase fuse timer to 1.2 seconds
-Make it so when a concussion nade is thrown, every 0.3 secs during its lifespan, three times, it will make a beep increasing in pitch
(Like ding ,diiing, diiiing,bang)
This is something to help the skilled player dodge the nade a bit better, where if they hear the first beep they have 0.9 secs to react and run, second beep 0.6 and 0.3 for last. This would notify people that a concussion nade is coming so people can prepare for it, and also be a sort of minigame for your reaction times.
I feel these may be a bit better for making Thunder viable, but not broken, rather than just increasing the CD.