What to do with EXP now..?

[Zhronne]

They have implied in several places that new things to merit will be added to the game (such as possible merit for increasing 1 handed weapon dmg).

Yes but on the long run this thing, just like removing merit caps (Originally Byth's idea which I wholeheartedly supported) doesn't solve the issue, it just delays it.
You can get XP so fast these days not even something appearently expensive like a 10>15>20>25>30 series of upgrades is gonna require a lot of time to get completed.

I'm not saying they should go back to lv75 FFXI model (it would be impossible even if they wanted to anyway), but they have to be thinking about a long term solution to make so XP is still interesting for players.
Being able to convert surplus XP into IS, Cruor, AN, CN or just plain items could be a cool long term idea, in addition with the merit categories expansion.

leeching afk in a worm pt for 80+hrs does not

If we were talking about 80hrs, yes I would agree. But what if you make that 16000 hours? Sounds like a big "effort" even if you're just afking lol
My only concern with giving "cool" items with XP points is that people with several accounts (and RMTs) would clearly abuse of that.
But if you use it as a way to enhance availability on the market of certain items (to slightly lower the price) or to give r/e stuff sure, why not.
They just need to make so the amount of XP required will be really high, and we'd be set.