ilvl scaling on equipment.

The new Aetheryte earings scale their ilvl to your level.
While we don’t know quite how much of an effect this will have, or if it could even compete with actual ilvl relevant gear (perhaps it’s only to slightly offset the fact that you’ve equipped an accessory with no real stats) could this be something they extend to other equipment in some capacity?

Perhaps not too widespread, it’d impose too much on the classic gear train and relic systems if you could just equip this ‘dynamic’ equipment at level 1 and never need to change them, right up to 80. But there could be some place for it.

How about the ring slot?
We have two ring slot options, and yet unique gear sets only allow us to have 1 of each piece, only 1 Ironworks/Sharlayan/Scaeven ring for example, so there’s always some compromise at a lower ilvl or less optimal second ring.
What if there was an exclusive, ilvl scaling Relic Ring for each job class?

Acquiring it via unique job side-quests, something we haven’t seen yet because this wouldn’t be mandatory like the core job quests, or simply via acheivements.
It could have a set of stats tailored specifically to that job (e.g. Spell Speed for BLM) to serve as a slight buffer for under-geared jobs, and as a guide to indicate what sub-stats that job should be aiming for.

From Game Watch Interview with Yoshi-P at Paris Fan Fest (2019/2/3)

Q: Will the preorder bonus item, the Aetheryte Earrings, stack with other EXP-boosting items?

A: It will stack up until a fixed amount, but there's a limit. It also has a new system where the item level rises with the player's job level. You can wear it at level 1 and it'll automatically get stronger as you do. We'd been discussing this for some time, and if you preorder Shadowbringers, you'll receive the item beforehand so that you can use it to prepare for launch.

Q: It's a great system. Are you thinking about developing this system into something else?

A: No. In a way, this system makes certain other items worthless, so we don't want to abuse it. If we did, then other items would lose meaning aside from appearance. If it were to be a region-specific effect like in Eureka, then maybe. Other than that, it'll absolutely need my approval in order to be used.

I'd rather they add additional accessory/ring options, maybe from EX primals or something like that with half jumps in ilvl so 385, 395 etc. Maybe a drop like the old leviathan mirror that allows you to upgrade it by 5 ilvls that gets added when they unlock savage.

I don't really think they need to do ilvl scaling on anything more than items meant to catch you up to last expansion's lvl cap. If for example they let your 1st tier savage weapon or your 1st stage relic weapon scale in ilvl then the only reason to get the new savage weapon is if it glamours. They would then need to make all weapons or armor scale then if they did that. I think for things like the preorder earrings it's fine tho.

I think for the preorder earrings it's fine, because they will probably only have mainstats on them, like the others of their kind like the ala mihgan earrings.
Also the amount of a single mainstat was a bit lower then that of an actual earring of that ilvl, so it wouldn't be to game breaking.

I can't see them adding this effect to other pieces of equipment because the main reason they came up with it is the fact that the previous EXP items effectively made you lose out on a slot as you wouldn't replace them when you levelled up. It's more of a workaround to a previous issue, not so much a new feature you'll starting seeing on gear in general.