What's wrong with your HEAD?

[3298]

Yes you could add something! ... well, to your list commands library.
Proposed name: LHEAD
Proposed implementation:

Code:

::
  CK1&Dispatch
  BINT5
  ::
    DUPNULLCOMP?
    case
    ::
      # 501
      ERROROUT
    ;
    CARCOMP
  ;
;

If you want to be even more efficient, you could investigate how stable PTR 1933C is across ROM versions (or at least across the ROM versions you want to support), and possibly use that in place of the innermost embedded subprogram. With that modification LHEAD would be pretty much identical to a theoretical fixed version of HEAD, except it's missing the string handling part (but because RPL strings have a size field, HEAD's length-checking approach is fine for those; no need to duplicate that code).
I only replaced two 5-nibble commands by two other 5-nibble commands, (DULENCOMP #0=case became DUPNULLCOMP? case), so an adventurous person could even fix their ROM in situ without much headache, but I don't think there are many people who would actually do that.
As a library command LHEAD would obviously have the performance penalty and the length of a romptr, but since HEAD is one too, we don't exactly lose anything there.

TAIL is already as good as it can get. Well, apart from the romptr thing, but if the developers were out of space in the permanently mapped part of ROM, that's one of two solutions, the other being the flashptr introduced with the 49g: 12 nibbles long compared to the romptr's 11 nibbles, and slightly faster (though for long lists this becomes irrelevant because then TAIL spends most of its time walking through it; for TAIL this is unavoidable because it needs to copy all list elements except for the first one to a new list).