Probably not. I don't see much in these new Canons for happy Sony users. But for millions of Canon DSLR users like me, who have been waiting (and waiting) for years, now we really have something to move up to.
Canon has also played an ace card with the new super-teles, and a timely one with Olympus' problems. M4/3 has found a solid niche among wildlifers who need the reach but without the massive weight and huge cost of those big white primes - lots of impressive evidence on the Olympus owners thread.
On the face of it, 600/800mm at f11 doesn't sound very appealing, but in 'equivalence' terms a 400mm lens at f5.6 on M4/3 (and say 1/1000sec at ISO400) is the same as 800mm at f11 on full-frame (1/1000sec at ISO1600). Same framing, same depth-of-field, same shutter speed and shake resistance, and same noise (same total photon capture). On a DSLR, that would still be impractical because the AF wouldn't work and the optical viewfinder would be too dark, but with mirrorless the on-sensor AF works just fine and electronic viewfinders automatically compensate for lost brightness