[Ichneumon]

Mutations are a LOSS of information.

No they are not. Sometimes they are a loss of information (e.g. excisions), sometimes they are a change in information (e.g. point mutations), sometimes they are a gain of information (e.g. duplications).

And, a dinosaur with feathers is a dinosaur.

Why is it not "a dinosaur with a bit of bird"?

[DittoJed2]

No they are not. Sometimes they are a loss of information (e.g. excisions), sometimes they are a change in information (e.g. point mutations), sometimes they are a gain of information (e.g. duplications).
Duplications does not equal the kind of added information that evolution requires.

Why isn't it a dinosaur with a bit of a bird? For the same reason that a dog with fur and a long tail is not a "bit of a cat." They are two different kinds of creatures.