What if Tryndamere's Q was bonus damage on hit rather than bonus ad?
Instead of 5 / 10 / 15 / 20 / 25 attack damage plus 15 / 20 / 25 / 30 / 35 attack damage based on missing health,
30 / 45 / 60 / 75 / 90 on hit physical damage based on missing health (it doesn't double in a crit)
alternatively,
20 / 30 / 40 / 50 / 60 on hit true damage based on missing health (it doesn't double in a crit)
The on hit physical damage would do more damage on a standard attack when tryndamere is at less than 75% health, but less damage on a crit because it is not doubled, so he doesn't automatically win his lane because of a couple early cheesy crits. He still does a lot of damage with his auto attacks and his crits still hurt, they just aren't quite a doubling of his normal damage on attack; his average damage is about the same with this change as it is currently.