The keyword there was "slightly higher value of cash shop stuff".
Like, say the cash shop has a variety of basic services and cosmetic items. Looking at the GW shop right now, I see a bunch of costumes for $6.99/each, and some basic services that range from $10~15.
One example of what I'm suggesting would be to allow one use of any basic service per month + 1 costume of choice for $13-15/month. The basic idea being, you don't get any kind of advantage or anything you couldn't get from the cash shop anyway, but by being willing to pay an optional sub fee you pay a flat monthly rate and receive a value from the cash shop that slightly exceeds that. There are ways that could even be encouraged, by offering subs a 3 day advance on new cash shop items, etc.
Nothing that would change the game, offer any actual advantage, or prevent anyone from playing it for free and deciding what and when they wanted to purchase something in the cash shop. Just an optional method of offering regular support, while receiving a minor discount/additional value from the cash shop in exchange.
XI Wiki



