Let’s take for example a fully evolved hero at level 30. You have 4 active skills and several passives. You can invest 30 points into each of the 4 skills for a total of 120 points.
For each level you got 2 possible points to invest. So the same hero at level 30 has 60 points to invest in. So my Zomm may be completely different than yours. For some heroes, it may be beneficial to invest in strong basic attacks. You could choose to make your tanks ultra tanky or a bit more offensive. And passives should require investment as well to improve their effectiveness.
Once you’ve customized your points, you can complement it with runes.
To reset your skills, you have to pay gold. The constant resetting will more than make up for the gold people will not spend on leveling up all skills to the max (in the current format).
This would add an element of strategy.