Hello Kelsey,
I wouldn't say, that RBPD is no longer relevant. It is still an option to create your business blueprint in SolMan 7.1. SAP/IBIS stopped updating RBPD about 2 years ago and RBPD will not be available in SolMan 7.2. RBPD is an improved version of SAP's BPR content + additional SQL checks, e.g. RBPD not only takes a look at transaction usage but also checks table entries etc. to determine process usage.
What options you use to create your business blueprint is your decision. It really depends on where you are currently at and what you are most focused on, e.g. if you need a structure very fast for regression testing, Blueprint Generation might be an option, if you want end to end processes the technical ACH structure generated with Blueprint Generation might not be the best option.
SAP will support the migration of the Business Blueprint from 7.1 to 7.2, e.g. you could still build your business blueprint in 7.1 with RBPD and then migrate it to 7.2. A lot of SAP customers will have to do that once 7.2 is out. SAP also articulate at TechEd this week that you don't have to wait for 7.2 to start your blueprint efforts.
SAP had a session around Business Blueprint at TechEd 2014, I gave one at Sapphire 2015 and there will be one in November at the Managing your SAP project event in Las Vegas
Take a look at the options and select what's best for you/your company! There have been very good customer presentations around RBPD at TechEd this week.
Good luck & Kind Regards,
Heiko