I agree that demons which appear in Megaten games should have a generic series qualifier, and that the qualifiers should be either spelled out or abbreviated "mt"/"smt" consistently, but I disagree with human characters having their qualifiers simplified away from ones that are specific to the games they appear in.
Take post #5789647. Right now, except for aleph (megami tensei) (who IMO should be tagged "aleph_(shin_megami_tensei_ii)") and demi-fiend, you can tell which games the characters are from just by looking at their tags. If these BURs go through, that information vanishes. It could, in theory, be replaced by wiki entries or notes labeling the characters on this and similar posts, but it would still take more effort to find where they're from.
And for what purpose, exactly? Any demon that appears only in a single Megaten game might conceivably be brought back out for an upcoming entry in the series, but I doubt that's going to be done with Aleph or Kazuya, except maybe as a cameo appearance where IMO it still makes sense for them to be tagged with their game of origin.
I think stephen_(shin_megami_tensei), who appears in six of the SMT games, is the only human (sometimes) character deserving of being treated like the demons are. Ironically his two pieces of art are deleted.