Adding something that makes it a little bit clearer what you've maxed and have yet to purchase would be helpful. Once the skill tree get's large it can be a little tricky to quickly see at a glance.
It might help to just grey out maxed skills? That way, only skills that have yet to be fully purchased would stay in colour, making it more visually obvious where to go next.
Related; the skills tree isn't centred on screen when you enter it. I needed to scroll a bit to the right every time to get to the column with the hazard stuff, but there was extra space available on the left every time.