Yes the old SMS/MMS needs to dieWow! I just got this today and it's great! Android finally has good text messaging. How many tries has it taken Google to finally get something like iMessage? ? Anyhow the only issue is is that it'll probably never work between iPhone and Android, but someday SMS has to die and RCS will finally take over.
However like the E part of Imessage that has little or no traction outside less than a handful of counties and is largely dead in the water internationally, RCS also wont have it easy.
RCS will also to have to battle against the existing dominant apps but should prevail as there must be a successor to sms