If they did this and have success, it makes you think the state of melee carries or melee DPS in general needs some serious work(imo).

^ This x over 9000

AP Tryn is a huge problem in this game whether you believe it or not. There is very little counterplay to it. This is essentially a fact. You're saying that just because AP Tryn is broken they can't fix him because he sucked for a long time and deserves his time in the sun... even though the games that he is in are very un-fun. That makes very little sense. It really just makes you sound like a whiner and furthermore someone who can't compromise. I'm sure Riot wants to change Tryn, but AP Tryn is a terrible answer and solution to this. He's just purely annoying.

Trynd needs the most attention of the 4 carries because of his ass backwards kit and Riot chose to nerf it to the ground rather than actually take a good hard look at it

He's completely UN-FUN to play as an AD Melee carry because unlike Nasus he doesn't have a strong late game let alone a fun late game, its a complete pain in the ass just getting to enemies let alone hitting them! Its like pulling teeth knowing the only way you can do damage is building damage and no defense while you have absolutely zero ways of defending yourself

So when he finally starts tearing into people because Riot flat out REFUSED to take a look at him AP Trynd is a message saying "MY KIT SHOULD BE LIKE THIS! I SHOULD BE ABLE TO DO MEANINGFUL DAMAGE, GIVE SOME SORT OF UTILITY TO MY TEAM, AND SURVIVE! I SHOULD BE USEFUL LIKE EVERYONE ELSE! PAY ****ING ATTENTION TO ME!!!"

I'm not sure if the message has sunken in yet to the thick skulls at Riot, but I hope so.

The state of melee DPS is hard to balance in the first place.
There are a lot of factors to consider.
Obviously the first factor to consider is the fact that they are melee. Usually compensations that are given to melee champions are gap closers and CC. However, champions who are actually meant to carry and deal a lot of damage can't be overly tanky either.
You end up easily getting to the point that the melee carry either is way too powerful and can deal with people in just a couple of shots or they didn't get what they needed and get CC'd to death before they are useful. This is exactly what we see happening with Yi and Fiora and it's almost near unfixable.

Darius is actually a great example of what I'd consider a good melee DPS. The longer he is able to stay in someone's face the more his DPS goes up. This is a rewarding factor that makes him want to play a specific way. However, his front end burst isn't necessarily overpowered either. If he had the burst that R-ADCs had then he'd just be insanely broken so instead he has ramp up time.
For melee DPS to provide something meaningful to the game while still being controllable they need to be on the tankier side with a ramp-up time. Even Vi is an example of this. The longer she sits on someone the better she is. It really is one of the only ways that she can be good. Jax might be the single best example of this paradigm.
World of Warcraft dealt with this slightly differently by giving Melee DPS a **** ton of silences and CC. The only problem with this is health pools don't translate well especially when you consider 5 other people also being able to do the same thing.

exactly

Melee ADC needs to build damage to deal damage (obv). But then they blow up in team fights. They need the bulk and be some tankyness in order to deal damage, but at that point, they stop being melee carries and become bruisers.

I completely understand what you're getting at and I can respect that. However it still doesn't take away from the fact that AP Tryn IS ridiculous. Yes, Riot is forcing him to be played a certain way and I don't necessarily agree with this. However, his Q is adding a lot of problems in the game. At the moment the cooldown is just way to low and way too strong for AP Tryn. He can give himself upwards of half health in about 5-6 seconds all the time. The problem is, if the cooldown is nerfed then AD Tryn gets nerfed as well. I think that a new idea needs to be added in. Perhaps they can increase the CD on Q signficantly but lower it by a percentage of AD that he has. This would force the itemization to be a certain way while still giving AD Tryn some sustain.

Which is why I believe honestly they should be converted to melee bruisers of some sort because quite frankly they just can't fill the role that ranged adc fill while being glass cannon because they unlike r-adc need to be in a danger zone to get the job done

Its way too risky to get very little payoff considering the r-adc does the exact same thing while being safer and more reliable

Ewww, Tryndamere players...

Plz you're probably a Diana or Xin player

You should know the pain