I think the option lists could be worded more precisely, whilst retaining its
current simplicity. Currently, we have:

++ (1) RSA and RSA (default)
++ (2) DSA and Elgamal
MS (3) DSA (sign only)
MS (4) RSA (sign only)
S (5) Elgamal (encrypt only)
S (6) RSA (encrypt only)
MS (7) DSA (set your own capabilities)
MS (8) RSA (set your own capabilities)
++ (9) ECC and ECC
MS (10) ECC (sign only)
MS (11) ECC (set your own capabilities)
S (12) ECC (encrypt only)
S (13) Existing key

This is confusing in a few ways:

1. "sign only" actually means "sign and certify"
2. "X and Y" actually means "X master and Y subkey"
3. "set your own capabilities" includes encryption only in the case of RSA

I am happy to keep using "sign" to mean "sign and certify", since certify is a
cryptographic signing operation; but the others could be clearer. So instead, I
propose:

++ (1) RSA (sign) and RSA (encrypt) subkey (default)
++ (2) DSA (sign) and Elgamal (encrypt) subkey
MS (3) DSA (sign)
MS (4) RSA (sign)
S (5) Elgamal (encrypt)
S (6) RSA (encrypt)
MS (7) DSA (custom capabilities, except encrypt)
MS (8) RSA (custom capabilities)
++ (9) ECC (sign) and ECC (encrypt) subkey
MS (10) ECC (sign)
MS (11) ECC (custom capabilities, except encrypt)
S (12) ECC (encrypt)
S (13) Existing key

You could also leave out "subkey", if you feel that is too verbose.