If it's a simpler game without much of customization go for evolutions, these are an easy way to keep game varied and interesting. And besides, if pokemon/dbz taught us anything is that changing forms is cool.
If you have complex systems (like equipment and/or some sort of enchantment/slots where it's possible to change units weapon type and add special effects) then idk.
Both systems can be amazing if you invest time in them.
If it's a simpler game without much of customization go for evolutions, these are an easy way to keep game varied and interesting. And besides, if pokemon/dbz taught us anything is that changing forms is cool.
If you have complex systems (like equipment and/or some sort of enchantment/slots where it's possible to change units weapon type and add special effects) then idk.
Both systems can be amazing if you invest time in them.