Some people are excited, some are denouncing this. One thing is for certain: this is a huge buzz that will not just affect Canon shooters but shake up the market for other brands as well. Studio/landscape shooters will be flocking to this 50MP body if all goes well, and suddenly Nikon and Sony will have to have something like this.
"if all goes well".
If by that you mean "Canon delivers a FF sensor with competitive IQ." (better DR, no pattern noise)
Consider that Sony is also expected to deliver a FF sensor in the 40-50MP range early in 2015.
If I had to choose between (say) a 46MP Sony Exmor based camera that was just as good as the Nikon D810/610 or a 50MP Canon sensor based camera that had the same IQ as the 7D2, I'd still go for the non-Canon camera because simply having more MP doesn't give me a better quality picture.
And in 6 months time, maybe that will be the debate here:
"Canon has more MP, better AF!"
"Sony has more DR, better IQ!"
... but the problem for lots of us will be that a FF sensor that performs the same as the 7D2 sensor won't represent anything new or better: there will be just more of it.