Wow, we've stumbled on a pretty interesting debate in potential Realmuto trade as there is a wide disparity in how people are valuing Alfaro vs Realmuto. There are some people whose posts I almost always agree with, but in this case diverge.
To me, Realmuto is arguably the best all-around Catcher in MLB. If he is not, who is?
Alfaro, in my opinion, is talented but with some glaring weakness (contact rate, OBP, blocking balls) that may or may not improve. At this stage of his career, he is likely in the 12-20 range as far as Catcher rankings go.
Realmuto would therefore be a major upgrade and worth pursuing. If I can get Marlins to bite on Alfaro, Nick Williams and either Medina or Howard, I do it in a heartbeat. If they insist on Sixto............ugh....ouch...his seemingly fragile health causes me to ultimately still do it.