Hey,
I wanted to suggest actually the deletion of Yoton, it isn't only the only combination of 2 elements, but consists actually of the both best elements. It's pretty unbalanced for the game, provides better range and even a Lava aura that damages the people that attack. It's in the first place pretty good itself, but even consists even of fire/katon and earth/doton. Both of these elements have ranged jutsus that cover the most area, giving those 2 an enhancement together is pretty much an overkill and the lava aura added up to it...
Another thing I would suggest is that people are able to buy or change their elements they don't like for something different by their own choice, considering that getting a new element costs around 500k ryo, could you make that cost 1kk (1 million) ryo. It would add more custom capabilities to someones character and he doesn't have to live with an element he doesn't likes. I personally think that Suiton should get a fix too as it is pretty bad, it has nothing special, from what I have seen atleast. I would suggest because of that, if you probably could make the water prison/Suiro not just for Swordsmen, but for all Suiton user. Suiton is basicly Katon, just less and worse jutus... if the Water Prison jutsu is too op for you might making Streaming Danger Tyranny be another option to add for water release.
Would be nice when you would consider my suggestions. Thanks and see you^^