Creating a weakness for ranged attacks

In a recent chat with Ghostcrawler, he stated that he'd love to give a meaningful weakness and trade-off to a champ having a ranged auto-attack. The range vs melee interaction is dull and lacks finesse of play, Tanks lack any significant role, and ranged AD's have been mandatory on teams for ages while every other class (Mage assassin tank support fighter) is optional and can be swapped out for different comps.

So what change can be made here? Well, my first instinct is that maybe we should co-opt a solution that's already in place with many abilities.

**All ranged autoattacks are now champion and minion blockable, behaving similar to Lulu's Pix passive. **

Exceptions: attacks against towers ( to maintain the strength of an ADC in a siege), empowered autoattack abilities (TF pick a card) and certain passive-empowered autos such as Caitlyn's headshot, Ashe's passive crit, and Quinn's Harrier ignore collisions. Placed entities and controlled clones or summoned pets do NOT block projectiles, such as Heimers turrets, Tibbers, or Leblancs passive.

Now, ignoring for now that certain champs would be overtuned and certain carries would require additional exemptions or buffs in order to stay competitive, what would the effects of this change be on game health as a whole.

Pros:

-Range is no longer king in lane. A shorter range or melee champion can hide among a minion wave to farm or engage, and a support can shield a lower ranged farming champion.

-Tanks have a distinct, useful niche when countering AD carries. Engaging on and sticking to a carry, or body blocking an allied carry opens up positioning games that weren't available before. The damage output of a carry can be interrupted WITHOUT needing to kill or totally disable them. And what does that mean?

-We no longer have to reign in powerful ranged carries with the threat of instant death. A positioning mistake no longer has to mean "Jack you dead". Engages and disables can be toned down without hyper carries having free reign of the world (see: the current meta) and a balance can be maintained with the ability to adapt and counter any strategy.

-Rich new worlds of Counterplay unlocked. Tanks and bruisers are no longer "engage on carry, cc or burst", now they have a defensive option. Waveclear is now a potent shield breaker rather than a push/counterpush alone. In lane, champions will be rewarded for weaving their ranged attacks in and among the wave, and positioning will be vital in all stages of the game.

-Ranged ADs will not, by virtue of their autoattack range alone, outshine all other botlane carry options. Melee ADCs can be the new hard engaging kill lanes. Farming mages will not get harassed out as a matter of course. Shorter ranged ADCs have a chance to shine.

Cons:

-Clarity is the big one. Clear indicators will need to be in place to show when an enemy is exempt from the minion blocking. A red indicator ring to show who you are targeting would be awesome. But even then, in the chaos of a teamfight, there will be more burden of understanding upon the player.

-Certain champs will need balance changes badly. In particular, melee champs who you need to bully early to keep from hyper scaling like Fizz and Yasuo will need nerfs, while traditional supports may need buffs since they lose a primary harassment tool. Carries won't be terribly hard to build advantages back into-just add situational minion ignore into their kits. For instance, maybe Vayne ignores blocking on tumble and on the third proc of her silver bolts. Maybe Kog ignores it on W (with an increased cool down to keep it from being crazy).

Thoughts? Concerns? I think for a big change in Season 5, this would be a great way to make the game healthier and more interesting.