Perhaps better to suggest just having an "Alternate cryptocurrencies" > "Development & Technical Discussion" subforum?
However, Bitcoin 'generic' "Development & Technical Discussion" does make a lot of sense, despite those who see others as impure.
"Bitcoin Protocol and Reference Client" is a rather limiting.
I don't care alt coin, just don't want them to contaminate this section
Please also note the description of this section: "Technical discussion about Satoshi's Bitcoin client and the Bitcoin network in general. No third-party sites/clients, bug reports that do not require much discussion (use github), or support requests." It's basically "Bitcoin Protocol and Reference Client".