One change to fix the problems that cause Tryndamere to be snowbally, cheesy, and non-interactive
Tryndamere's critical strikes penetrate 100% of his target's bonus armor, but does 40% reduced damage; additionally, tryndamere cannot use flat armor penetration and treats flat armor penetration as if it were critical strike chance; In other words, rather than 2*AD on a critical strike, Tryndamere does 1.2*AD on a critical strike that ignores bonus armor. If he gets an IE the damage would be 1.5*AD.
Here are what the numbers look like for 500, 750 and 1000 point critical strikes against a target with various amounts of bonus armor and 80 innate armor.
http://i.imgur.com/kVxVivk.jpg
Graphically, with no last whisper: black is current and magenta is proposed damage curve as a function of enemy bonus armor.
http://i.imgur.com/zFyCzfq.jpg
Graphically with a last whisper: black is current and magenta is proposed damage curve as a function of enemy bonus armor.
http://i.imgur.com/QhEdh5k.jpg
##Summary
This change would greatly diminish Tryndamere's ability to cheese lanes at level 2 or 3, and it would immensely reduce his damage to targets that have very low or no bonus armor, like carries. In fact, he does only 60% of the damage he currently does to squishies with this change.
As a trade off for doing far less damage overall, his damage becomes target agnostic-- it can't be reduced by bonus armor, only innate armor and large amounts of health or damage reducers like attack speed slows can mitigate his damage output directly, though his damage output already reduces itself by 40% for you.
Basically this change makes it so that Tryndamere doesn't really care who he hits, as long as he hits something. He does the same damage number to anyone, so instead of focusing on cheesing squishy carries in team fights as an assassin might, he focuses on just auto attacking as many times as possible regardless of the target as a proper fighter would.
###How would this make him a more reliable team fighter?
It gives him a definite role in a team fight.
Zyra and friends zone out bruisers like shyvanna from diving their kogmaw because she has a ton of peel and disables from which to give kogmaw plenty of free hits. In other words the value of her spells in terms of damage, given that kogmaw would otherwise be standing around and not doing anything useful, is however much damage kogmaw can do to her in those precious seconds during which shyvanna is locked down.
Tryndamere would provide zoning power. Unlike supports that specialize in peeling in a team fight to grant the marksmen and friends free damage, Tryndamere simply provides target agnostic damage on his own. Shyvanna would be afraid to dive kog directly even in the absence of disables simply because of the damage Tryndamere would do to her if she did. His ability to protect the marksmen otherwise is limited, but still present in mocking shout attack damage reduction and powerful slow.
He would be a very targeted kind of champion-- aimed at a very specific niche. He doesn't defend well against an assassin like leblanc, his specialty is body guarding against bruisers like renekton and j4. He does it by being immune to death from damage via the enemy backline and body blocking skill shots for his ad carry, greatly reducing the ad of the bruiser in question, and ripping them apart on the spot. Other than that, he wouldn't do anything particularly well in a team fight-- he doesn't clean up particularly well because of the reduced overall damage. He doesn't dive particularly well. He doesn't have an outstanding amount of utility.
He'd just do one thing well. Bodyguarding against bruisers and being a man while doing it. And I think that is more in line with his theme. Running from large team fights and focusing intensely on avoiding groups of potential challenges while pushing lanes is very non-confrontational and not in line with his identity.
