Throw awat the iLv system, implement a PvE Rank system.

[Nutz]

Ilvl doesn't gate a large group of people from doing content. There are requirements, yes, but if you don't meet them you are very unlikely to pass said content without being carried and none of the requirements are high (Ifrit Extreme would require full darklight and any weapon at or above level 70). I was actually pretty surprised at how low they set the requirements for many of these.

As for removing ilvl and replacing it with a PvE rank...you'd have to be more specific since that can mean a lot of different things as far as how that rank is generated. More than likely the result would be similar or the same, except that you wouldn't be able to increase your rank for alts without playing them the way you can collect gear for alts currently, resulting in gated content for players that actually can complete it. That or your PvE rank is character based, in which case you'd essentially have no requirements after your first job.