its 35% at level 1, and the flat boost is only 5 at first rank. from there it goes up by 5 for each additional rank to a maximum of 25. The scaling portion starts at 15 and goes up by 5 each rank.
I wouldn't have a problem with your suggestion except that I feel that Tryndamere has nothing to offer his team if he does not dominate his lane. He is a crappy team fighter when both teams are relatively even in gold, and he doesn't have hardly any utility to speak of. The power of mocking shout falls off sharply after the mid game, and after that Tryndamere is forced to play the split push game.
A champion can build enough armor combined with thornmail to straight duel tryndamere. The thornmail ensures that he cannot regen health while auto attacking you, and I've made threads on the specifics of the mathematics involved there. Between that and the armor and health, all you have to be able to do is put him down to 1 hp and then survive his dps for 5 seconds, and that can be done with about 4000 health and 400 armor against a full build Tryndamere.
At that point in the game Tryndamere isn't left with any options. He is a crappy team fighter at this point especially since the supports likely have quite a few actives with which to peel him, and now he can't even split push. In other words, Tryndamere's late game may be good but his "end game"-- where everyone has maxed their builds-- is terrible.
I think given his weaknesses and the fact that he doesn't have "50% bonus armor penetration" or on hit true damage or any way to specifically counter the tanky bruisers that he is often up against, or any way to RELIABLY kill a squishy important target end game-- no immunity to slow or doublestrike alpha dunks, no fiora ultimate, not nearly the utility of yasuo...
I mean think about it holistically. What does Tryndamere even do? He just hits things with his melee attack over and over. Thats all. Other light fighters have plenty of things that they can do, but Tryndamere does not. His entire kit literally revolves around his auto attacks. Fiora has her ultimate and riposte, Yi has alpha and meditate, Yasuo has a knock up and windwall.
In other words those champions can do things to help their team that doesn't involve positioning themselves very carefully to be in melee range of an important target but out of aggro range of their important crowd control-- a very difficult game to play. They have fall back patterns and ways to "cry for help". Tryndamere literally doesn't do anything if he isn't hitting something in the end game aside from perhaps landing a mocking shout, but landing the "perfect" mocking shout means being suicidally close to their entire team and open to chain cc and inevitable death without doing any damage at all-- a trade that isn't worth it. Atleast in the mid game mocking shout really feels solid and has a huge impact, and he can do some things and feels like he has a fall back pattern just like the other light fighters.
But as the game progresses and mocking shout falls off, he doesn't feel solid. That is why I think it is so necessary for him to win the lane hard, and why I don't think he should lose his bonus AD.
BUT
If he does lose the flat portion of his bonus AD, I strongly suggest putting some scaling on his mocking shout so he can rely on a fall back pattern and have something he can do in the latter stages of the game in team fights even if he doesn't have a huge lead (and not necessarily overbearing if he DOES have a huge lead)
