I'd like to suggest that some Texinfo commands could be marked as deprecated, with warnings could be introduced to encourage people to remove these commands from their documents/config files. Some rarely used commands could possibly even be removed at some point in the future.
@definfoenclose. I believe that this is used by Sphinx, so can't be removed immediately, but there is no real use for it. It was originally introduced for the Jargon File which wanted to be able to customize the Info output. This kind of output format-specific command doesn't fit in with the other commands in Texinfo which are "semantic" and format-general. It's an obscure way to create a new Texinfo command but one which does add some complexity to parsing Texinfo. I'd be happy if this one went. @smallexample and friends. Simpler to use @example instead. If people desperately want to use smaller fonts in the printed output they could use @set dispenvsize small instead, which is only used by texinfo.tex and doesn't affect anything else. @acronym. gnulib warns about use of @acronym (in top/maint.mk), the manual does not encourage it, and <acronym> has been removed from recent HTML standards. @refill. Does nothing. My guess is that @smallexample, @acronym and @refill should continue to be supported for compatibility with old documents that use them. @rmacro. I'd have to check but I believe that @macro can also be used recursively. I doubt that this is much used. @setcontentsaftertitlepage and @setshortcontentsaftertitlepage are already marked as deprecated and do nothing. I suspect that these aren't used much and could probably be removed. @inforef: Little need for this as Info files are nearly always generated from Texinfo source. There are other commands like @exampleindent or @clickstyle which are used for customizing the output, which is not ideal, but in the absence of an alternative I suppose they should be kept. I think @t, @i, @b and @raggedright should be kept as they are; even if they are "non-semantic", they are harmless, and may occasionally be useful. I'm not sure about @sp.
