Some people in my dojo are gifted with "monkey toes" -- they're long and veeery flexible. Getting their toes alive in a comfortable position during suwari waza is a breeze for these people. Me...not so much. My toes are short and don't have the flexibility I'd like -- I'm more on the tips than on the pads, which makes suwari waza difficult if I'm trying to stay low and not rise up and defeat the whole purpose. I don't think I'll ever have "monkey toes", but I am sure I could do something to improve my toe flexibility if I work at it. Has anyone ever tried this? Do you have a method that you used, and were you able to get results from it?
My toes have suffered much abuse over the years, particularly from several stubbing incidents. I have long feet and large big toes, and neither of the latter will now bend beyond about 45 degrees. As a result suwariwaza, which I used to really enjoy, is uncomfortable on tatami which are at all hard, as - like you - I end up moving on the tips of my big toes.
I stretch my toes every morning as part of my daily yoga practice, but unfortunately I think that this only preserves the status quo. If I had a lot more time I could probably make a little more progress, as the soles of my feet are quite stiff.
So I'm afraid I can't offer you any good news!