Hey Kall! So in-depth analysis here.
I personally like your style because, well, it's unique. While the new style you're trying out looks AWESOME, it really looks like many of the other art styles that there are already an abundance of throughout Tapastic/the Internet. Though that's kind of a vague description, I hope you sorta get what I'm getting at anyway lol What I liked about your style is that it was one-of-a-kind; if anyone who was a regular member of Tapastic saw one of your comics, they'd immediately be like "Yep, that's Kallehmono!" whereas this new style wouldn't be differentiated as well.
However, I do think the new art style is a much better representation of your abilities and skills as an artist. If it's a style you want to try working in, make sure that you're able to stay consistent with it. Practice with it, and maybe do a few test strips with it (so your readers can give an opinion too!)
As for the body shape, how well would the head actually fit in with the body? As you have a very cartoony, "chub" look going for the body, and a more semi-realistic style for the head. Those might clash and might not work well together. But you'd have to try it and see what happens. This is another case as well where the body looks a lot like how everyone else draws their comics; so if you did choose this path, think outside the box, come up with a way for it to be your style, and not just a reflection of others. Whether this was your intention or not, I know you're super creative when it comes to your style and ideas, so I'm sure you'd be able to make a style all your own that still reflects that creativity from former styles
ALSO, if you stick with that thick linework (like the "border" style you've got going"), maybe tone it down a little on the body? The head's been fine all along because it's just a circle head lol but when you make the border that thick on the body, it takes away teh flow and movement you could otherwise achieve with thinner lines. Everything just sorta reads as one big clump when you do it that way. You can keep the border, but maybe just make it half as thick? Especially if you decide to stick with your original style.
Overall, make sure to do lots of experimenting before you make any big leaps. It's your decision, it's your comic - do it in the style you want. Don't worry about "what sells" or "what the readers will want"; people already recognize you for your style and characters, and they enjoy it (as do I). Whichever one you choose, both are awesome in their own way and demonstrate different but equal values of your style and skills. Good luck ^__^