>>58220105 (OP)
The problem with Megas for me is that they stay so close to the base designs but with some extra details that don't really give them much identity on their own.
So if I hate the base Pokémon the changes a Mega can offer usually aren't distinct enough to make it good.
If I love the base Pokémon the Mega will usually feel excessive and muddying what I like about it.
The few I think are great are the ones where the base design /just/ miss the mark, and the changes of the Mega really brings the design together.