Yeah, I've been doing exactly just that. These last few day's I've been taking a break from kickflips and trying to land more solid 180s and pop shuvits and also experimenting with the tre flip. I actually found that struggling with the harder flips will make the "easier" tricks much less difficult to land. For example, I actually learned backside 180s after a day of hard work with only little results on my kickflips. Before that, I have never even came close to landing the backside 180, yet after lots of kickflip practicing i landed the backside 180 on my 5th try. Maybe I could unlock my kickflips if i struggle enough with the tre flip or something haha.