No, Ki is no more. They decided that lumping all those classes together didn't make sense. More than likely you will see them scattered across other power sources.
Though they're not mentioning it here, my bet is that the other side of why the
ki power source didn't make sense is that the 'oriental' spellcasters really belonged in the elemental power source if it was there.
Guesses for the OA classes, long-run
ninja - shadow striker
sammauri - paragon path open to any defender
shujenga - elemental leader
wu jen - elemental controller
It's hard to figure what psionic classes will make the cut, or if they decide to come up with something new. I mean, probable role of the 3.5 psionic classes pretty much breaks down as
psychic warrior - defender
psion - controller (a kineticist could be a striker, but my guess is they want to leave that kind of thing to arcane and maybe elemental characters)
wilder - controller (see psion)
soulknife - defender or striker
ardent - leader
divine mind - defender
lurk - striker
If I were to guess what they actually do in PH3, well, with WotC axing the
ki power source it makes the two power sources idea more tenable, so...
monk - psionic striker
soulknife - psionic defender (soulknives figure prominently in Kalashtar culture, and putting two classes in the ECS would take up too much space, and there's a surplus of strikers)
[new class] - psionic leader
telepath - psionic controller
hexblade - shadow defender
ninja or assassin - shadow striker
necromancer - shadow leader
shadowcaster or beguiller or illusionist - shadow controller