What happens to our iLevels?

[Ultimatecalibur]

I think this is a bit off. I don't see them releasing new tome gear (which it sounds like the new AF will be) that's the same ilvl as current gear (Poetics and Dreadwyrm). Even if there weren't an expansion, just a 2.6 patch we'd be getting i140 gear upgradeable to i150, going by the current pattern (and i150 raid gear if there were more Coil). I'd say at a minimum the new AF/ Alexander gear will be i150 (possibly after upgrade), but probably higher to fit in some gear progression between 50 and 60.

My point is that we should not expect growth higher than i130 before level 60 endgame. The required ilevel for Heavensward will be starting from i100 (i.e. Keeper of the Lake's rewards) meaning that there are still 2 ilevel sets before i130 gear is required.
I'm expecting the AF2 sets to be Job quest rewards or a dungeon token trade in similar to how AF1.5 is now and not tome gear (though the new tome gear with ilevel equal to Alexander's rewards may be dyeable enhanced versions, but I doubt that) because they are already being advertised.

I would expect that, assuming previous trends continue in some respect, there will be a set of unlimited tomes and capped tomes probably with entirely new gear and the unlimited tomes gear will be an upgrade for everyone (ie. bested only by the gear form capped tomes and either version of Alexander). Probably a 'darklight 2' set purchased with the uncapped tomes at ~ilvl 150 and the new AF purchased with capped tomes at ~ilvl 170.

I doubt that. Poetics will likely be made unlimited and a new tomestone/tomestone like will be introduced to purchase the Alexander NM equivalent ilevel gear from (which can then be upgraded with a token gained from Alexander HM).

I always thought it was weird that iLvs suddenly start going up by 5's at lvl 50. It seems so arbitrary.

They could just change it to go up by 1's (so i100 would be i60 and i135 would be i67 but still have the same stats as now) and it would take a lot longer for iLvs to outpace real Lvs and get up to ridiculous numbers.

Ilevel is a factor in the gear stat formula.