>>57907607 (OP)Great-Tusk is a very good design. Pokemon Paradox is not a gimmick. You're confusing them with Mega-Evolution, Z-moves, Dynamax and Terastal.
And it's normal that Donphan doesn't evolve into Great-Tusk, as it's a distant ancestor. After billions of years of evolution, they're not quite the same creature, even if they come from the same evolutionary branch. So they are related, and have DNA in common, but are still so different that they can no longer be called โDonphanโ. It's a bit like Mew, he's everybody's ancestor, but nobody is Mew or can become a Mew again.
The evolution from Phanpy to Donphan is one of growth, from child to adult.