What if they incresed the actual level required to wear darksteel/myth/allagan/(un)weathered/high allagan/ironworks/dreadwyrm (and LotA/ST/WoD) gear from 50 to 60?

Meaning you'd be naked as a "fresh" 50 when expansion hits and you'll need to grind 10 levels to reach 60 so you equip your gear again.
Meanwhile you'll have to use 1* crafted stuff and eventually some new level50-59 gear that becomes available...

Then you reach lv60, and you can be item level 130 again... just to grind the new set of lv150+ gear >.<