Hi! Thank you for your comment. We've heard from a few people who, like you, prefer Asterion's previous body type. Looking back I see that we should have foreseen it, but there are some technical and practical hurdles that make it tough implementing an option to display his previous body type.
Mainly, his previous sprite set has fewer expressions and they work differently (a lot of his expressiveness comes from manually picking how his arms will be, which is not a feature we use for his main sprite set.) On top of that the majority of the customisation options were drawn for his main set, so we can't overlay them onto the old build. Overall we planned a lot of content, and prepared the assets, counting on Asterion's fully-healed body type being the one and only available past a certain point in the game.
Looking back we should have guessed that some people would prefer his previous sprite set. It's very understandable. But sadly making his intermediary body type work for the rest of the game would be a very significant undertaking. The easiest implementation (just switch over the sprite set without a second thought) would be janky, there would only be a handful of facial expressions and it'd be liable to break often. Meanwhile equipping his intermediary set with everything it'd need (clothes variations, all the expressions, editing CGs) would be a massive undertaking and would really take a lot of time.
That said, I think it's worth saying that Asterion's fully healed sprites were the first ones nanoff did for the game — and it's been something like a year and a half since that happened. Since then nanoff's improved quite a bit and he's been doing improvements to Asterion's sprites, which should make the whole experience better for everyone.