Tryndamere's Ultimate
I think it needs a small nerf to bring it in line. Specifically, slightly reducing the ability to cast his ultimate under Crowd Control. It currently can be cast under any form of control.
I think suppressing effects should actually disable its cast.
Why? Because summoner spells (including cleanse) cannot be used against suppression. Why should Tryndamere have an ultimate that ignores suppression when all current suppression effects require a channel (including Skarner, even though he is able to move during the channel). There is no other champion skill in the game that can ignore suppression. The only ability that can break suppression is QSS and it's upgrade, Mercurial Scimitar, which is mostly reasonable due to a 90 second cooldown.
I feel Tryndamere's ultimate should be allowed to ignore most CC, just not suppression.
