Could have a weighted ilvl calculation based on tome costs, as there's a more or less proportional investment vs return (at least on mainstat), although weapon is a slightly different matter. I came up with a spreadsheet a while back in 2.0 that did this, before ilvl was shown in game... think I may have posted on forums somewhere.

For getting rid of "accessory cheating" to boost ilvl, could ignore from calculation if that class/job the character is on would be unable to need on that accessory class. (e.g. don't count fending for non-tanks, but do allow maiming accessories for monk, etc) Or count them at half the ilvl.

That would prevent ilvl cheating to a degree, but it's not really a big deal to check someone and notice that they have wrong gear on for their class, and ilvl really doesn't say much about a player anyway.

So overall not really bothered, but I don't really do much stuff with random players, so is probably less of a concern for me than some people.