The one on the right needs a goblin green base.

Dull guy feels much more like he's been around the block a few times. I'd go with that route and lean even more into it.

It depends on what you like. I like both for different reasons. I like having pretty high contrast on my minis, so the darks are dark and the colors are vibrant. But some people like the dull look too.

With respect, I feel that both are halves of very similar end goals. For example, the model on the left (A) has edge highlighting, but lacks much contrast. Whereas, it's counterpart (B) has an abundance of contrast, the larger pieces seem to lack the definition that edge highlighting can produce. While it might be a bit of work to get A & B to each resemble the same C, there are a number of things they don't have in common that their neighbor could benefit from. 🤙🏼

Personally I say go bright.

I'd rather play with or against a garishly bright army than a dark one trying to look grim dark. I'd push some brighter highlights though, right now it looks a little flat and just mixing in a touch of yellow and light glaze should give them more depth.