OOohh, tell me about it! In my first year of animation I also did my assignments with the mouse, before being able to afford a tablet.
I look at some of the drawings from that period and I think I simply could not replicate that now.

Daichi looks totally good in this one I say

I used to work in Adobe Illustrator, so the mouse thing wasn't too big of a deal, as I got really good at manipulating anchor points. When I moved into more efficient software, like Photoshop and Manga Studio, that's when I either had to scan sketches or invest in a drawing tablet. It's strange how a less accurate form of input can look good if you really do practice with it as opposed to using the more accurate form.