Since Yoshi said that our current gear won't be immediately obsolete (and it wouldn't make much sense logistically) I'd expect i130 to be at least good enough all the way to 60, though probably outperformed by options in the 55-57 range. I mean, when you get gear form quests/ dungeons it's not like you get a whole set at a time, and dungeons usually require gear a bit less powerful than what they drop. So if the first dungeon is dropping i130 stuff, that would mean that you'd probably need to be about i130 to complete the next one.

This is probably not much of a problem for people playing right now, but for new players that aren't going to grind a full poetics/ WoD set when they hit 50, but rather continue leveling, the gear requirements would skyrocket and require that they stop leveling to grind out a full set of up to date gear. Because of this I'd expect that there will be ample opportunities through quests and dungeons to gear up in a totally new set before the requirements shoot up above i100 or so.