Tryndamere
His ult lasts for five seconds. FIVE WHOLE SECONDS. That's almost twice as long as Kayle ult, and almost like poppy ult except others can still damage you and cc you. Combined with his crit based kit, he can pretty much do anything. Even poppy has to consider building some tank items.
If that does not deserve a visible ult indicator like the indicator on annie's passive (which by the way, Annie has an instant aoe stun, so by fixing veigar to not have that, you should be fixing annie as well.) I legitimately cannot express how horrifically unbalanced this is. Do you expect everyone to use their hard cc onto tryndamere despite him not being able to be killed? If they do, the rest of trynd's team annihilates them, and if they dont, trynd can do whatever with his crit-focused kit. Destroy towers with the enemy having no way of stopping him other than hard cc, determine entire teamfights by simply pressing R, diving in, killing the carry, or if not, burning the entire enemy arsenal of hard cc, then proceeding to win anyway.
You might argue that he can use it for psychological purposes. to scare everyone into running. however, with a ridiculous cooldown of 110/100/90 seconds, not considering cdr, this is pretty bad.
Champions hit level 6 pretty fast. it would be nice to reduce the invincibility length of trynd's ult at earlier levels, as well as give an indicator as to when his ult is up.