>>9356388Eh, it probably depends, such as what he has to work with.
In mecha toys you see lots of creativity and they usually have better gimmicky means of carrying out extra range of movements. Chemical Attack can do some crazy things. And RD ver ANIME achieves a good balance of aesthetics and articulation. Some model kits can be very complex with joints too.
Yamaguchi's only real attempt at that kind of more advanced "tools" was AY Optimus Prime. Shinkalion Eva was halfassed and sucked. It was decent for a first attempt but also fairly basic stuff except for maybe the shoulders.
Human form (including Evas) he can do great things with the most basic tools in his arsenal. But that's also not that challenging, if that makes sense? Back when he was making random robots with revolver joints there were some creative tricks and some were very poseable even by today's standard.
But action figures and kits became more complex since then, and usually we don't see articulation given more focus unless it's a robot that otherwise will move like a brick. Human figures usually get a pass with average posing, and don't go the extra like Yamaguchi. They can if they used half the tricks from RD ver ANIME. I think we need to see more Optimus level projects from Yamaguchi to fully see what he can actually do. But Kaiyodo never gives him that kind of budget.