If none of you can find an idea well here's what i think;
I-frames in this game are incredibly strong, because of how almost every spell has a long wind-up animation, making you able to easily dodge anything thrown at you (that isn't instant cast).
Put for exemple my matchup of Crane VS Karma, i do get openings thanks to my gears, but it does not matter at all as every single one of my spells have an atleast 1 second wind-up before hitting, and my sleep is 2 freaking seconds, my poison (for rp stun) is 1 second, the only way for me to win would be to end up like DiViNe, full +15 CCBD with maximum DEX and be RNG dependant, but i'm not a Fighter, i'm not relying on luck.
Shout's I-frame is way too long for how strong the spell is, it's a 45m 3second stun with a ~2 second iframe, on 18 second base cooldown (so 9 second with 50%cd).
Basically, you simply can NOT get hit as a Karma if you spam Shout.
I tried many things like slow then charge RP and KD with my 45m spell, but karma shouts right when my kd hits him.
I've also tried spamming dots whenever i get an opening, but he can shout WHILE getting hit and negate the dmgs.
Now yeah you can use it against them, but will you stay nearby the edge when he can RP confuse you/Stun you then ring you out ? well i did, it always ended up with me out.