1. i was somehow under the same impression elitekage but afro is right, we shouldn't jump to that conclussion, there's no reason to assume that, yet i'm willing to wait and see whether or not the manga confirms what we suspect.
2. yes afro, this is the dilemna, though hear me out. if the EMS only effect was to negate the blindness of mangekyou, it would make complete sense>ETERNAL mangekyou sharingan, but if this was all there was to it, why not just leave it at that.. why does itachi imply a new doujutsu? whether the EMS gives the user one new eye technique(example: a time-space jutsu like kamui or tobi's phasing ability) or in itself is the NEW doujutsu bringing with it multiple new techniques(example: maybe multiple space time jtsus like both kamui and tobis' phasing ability). or perhaps it doesn't and just amplifies the original mangekyou techniques, it apparently already upgraded susano'o.
3. significant or huge? eh, it looks BADASS, all i have to say XD
4. i personally hope his genjutsu is upgraded to itachi level, what's the point of being the pinnacle of an uchiha if your genjutsu ain't impressive as a fellow uchiha? >:]