Hey Giles, I like the character you have here. I've seen you posting various characters on the forum, and you obviously have some skill. Your characters have interesting ideas, cool detail, and are technically sound. But I feel like they all lack a bit in the basic form. This is the same problem that I struggle with, and oddly enough it was a paintover that Josh did on a character of mine that really helped me focus in on that problem.
With a little bit of tweaking to the basic form I think you could turn a good character into a great character. Without an appealing basic form all the detail in the world won't help it. Josh's image you posted is a perfect example. Very simple detail, very appealing form. Really study the shapes that make up the characters you like.
Here is a quick paintover I did to highlight some simple area's I think you could push it a bit more.
Anyways, I hope it helps and doesn't come across the wrong way. Your one of the few people consistently posting work and I think with some honest critique you can really push things further. Goodluck!