I don't really care whether S.H. MonsterArts does Showa or Millennium, as long as they do one or the other. The current figures look great, but I generally don't prefer the Heisei forms of the monsters, and as mentioned here & elsewhere, the Bato-Goji design restricts articulation.
Eh, most of Godzilla's articulation problems stem from the fact its spines interlock making turning the body impossible,, and the jagged texture of the sculpt as well as the way try to conceal the joints of the SH Monsterarts (unlike the Revoltechs), and this would apply to every Godzilla. GMK Goji in particular would fare no better. I only see Showa Godzilla really shining articulation-wise (if they ever do one I would love to see them do Mosu-Goji or the '68 one, whatever its called).
Although I don't understand why Bandai went with Moge-Goji instead of Bio-Goji, the latter is superior in nearly every way design wise.