You mentioned your current pain points on your spinning disk based system being "disk activity always >95%, b2b CPs, and de-dupe running 24/7".
99% of the time the AFF will definitely resolve this. An AFF is flash optimised, it bypasses layers in the RAID system to drastically improve latency/speed when writing to disk. When you add the fast IOP/low latency performance of flash, you should see an eliminaction in b2b CPs. Also take note that flash is more resiliant to a "full file system" than spinning disk. As your available capacity reduces the system doesn't need to keep seeking the disk subsystem for free space.
AFF also introduces inline-dedupe (at an aggregate level if you get on to 9.2), which will exponentially improve your post-dedupe performance.
Overall, moving to an AFF *should* be a good move for you. But definitely get advice from your SE/partner that is specific to your environment.