I don't really think dropping PS2 support is an option for SE. Would it allow them to make some improvements to FFXI, of course, but in their eyes I'm quite certain the cost is too high and the gain is too low.
The up side: Improvements to FFXI would realistically only make existing customers a little happy, for a little while, without generating many new customers.
The down side: Lost revenue of customers that don't move over to either PC or 360.
Personally, I think the long-term benefits of dropping PS2 would pay off. SE would theoretically have more options for additional content, and therefore generate income from expansions and such, but who knows. I don't know how many of you have seen the Letter from the Developer they've been doing for FFXIV, but they're putting a considerable amount of effort into re-vamping the game to make it appeal to the masses. FFXI is never going to get that type of attention, it's simply too old.
Would I like to see PS2 support dropped for the possibility of a better FFXI? I would. Do I think it will actually happen? Sadly, no.