I don't think you need to fix your style or anything like that. However, if sketchy-messy lines aren't part of your style, maybe you could give this a try to see how your art would look like! You could also have fun with new brushes or play on different programs to see what you could add more to your art.
More more more details always is good to improve a quality of a piece of art! (again, needless to say that people put the amount of details they think is good according to the style they wanna give their picture, too much can look odd with some styles and too little can look 'empty'.)
As for anatomy, as usual it depends on the style, but a good anatomy sure gives more to a picture, I like to draw fantasy things for example but with the correct anatomy and a lot of details in the coloring/fur/backgrounds, etc. Though I'm FAR from good at that, I just like this kind of art and I'm trying to draw those things xD; I'm the slowest on earth I swear!
About the variety of things you draw, really just do what you like. I mean, if you force yourself to do things you don't like, you won't enjoy it and then what's the point? but you could do little practices here and there just to get a new perspective on things maybe. Like, it is said that knowing how to draw a bit of everything, in animals/humans/objects/landscapes is a good bonus for anything in art!
You could then maybe experiment new things if you feel like you only do the same thing over and over; create a new species for fun- do collaborations with not one but multiple people on one piece, etc. :3
I hope this helps a little!
For the art block when you get one, I'd suggest you to take a break or to draw things just for yourself/friends without thinking much about details, do memes or play games, etc. It's what I do, it doesn't work all the time but it's all we can do until the inspiration comes back (having so much ideas often result in an art block, we try to do all of them and we get frustrated because it's hard to draw what we pictured inside our heads, just relax and focus on one thing at a time).
There you go ♥ ~