If you like classic pixel sprites then you will still enjoy the visuals like I do but I understand the need for a new updated look. The only downside of Shadow Magic is its age. This forces players to adapt to the races unique playstyle rather than relying on a specific class that covers their weaknesses or abusing a classes ridiculous strengths.
Instead each race has their own specific units with their own strengths and weaknesses. There is no class system in Shadow Magic. The magic in Shadow Magic play a bigger role in the gameplay which 3 severely nerfed the impact of and made the game a lot simpler while also reducing army sizes from shadow magic from 8 to 6. As it itself is a standalone expansion to 2 that further balances the game while adding a couple more races, magic and units to the game. First off the game features way more content than 3.