I think that some traits have an unreasonably large effect on the species. And we attach greater significance to them after the fact which makes it seem like a

I think that some traits have an unreasonably large effect on the species. And we attach greater significance to them after the fact which makes it seem like a big jump. For example some fish evolved to have stubby lobed fins. That gave them some local advantage. It is just coincidental that the same change lead to arms, legs and wings. And these kind of big visible features need more than a few changes in DNA to happen. An arm needs to attach to something, have muscles and arteries and nerves. That can only evolve iteratively from something else. There is a reason that elephant trunks are also a nose.