Simplicity over complexity, time to change.

[Kazama]

You treat simplicity as something bad. Back from when I worked as some kind of designer there was a golden rule - KISS - Keep It Short and Simple.

KISS is mostly recognized as "Keep It Simple Stupid" - And it is meant to be applied in relation to over complicating things for no reason. Regardless, to apply KISS to a game is often really bad practice. It results in things like FFXIII where the game pretty much played itself and you watched cutscenes. http://en.wikipedia.org/wiki/KISS_principle

One of the problem with horizontal progression that it makes whole "ilvl or bust" goes beyond clouds. Every single situation will be min-maxed and people with non-optimal equipment will be shunned. And getting 5 sets of gear is a larger stress than getting 1 set.

That is not at all true. I gave you two very good examples both of which min-maxing weren't required. In 7 years of FFXI I don't recall a single occasion where people said no you can't do this with us because you don't have X item, and trust me my gear was nowhere near stellar or BiS. Same goes for Aion, never was I shunned from a group or run because I didn't have the right gear or stats or asked what my stats were even. In fact, you could block people from examining your gear all together.

Now on the contrary, I can't even get into some Leviathan parties or even Brayflox speed runs because the ilvl is set to 93+ and I chose to craft and meld an entire set on WHM as opposed to buy soldiery since it is not my main. I've actually sent tells stating I have over 100 levi wins on healer and to drop their ilvl req or invite me and met with rejection. Gearscore, as many anticipated, is the pinnacle of judging and measuring. No longer does it matter at all if you have completed content as long as you are above the ilvl that is all people care about.