I disagree. They can get screwed over, but they don't always get screwed over like you said. Gliscor and Staraptor in Sinnoh were both treated very well. They had different purposes and, despite both being Flying-types, they both got pretty much equal battling and development. Charizard and Pignite in BW immediately hit it off. They used their combination Flamethrowers and acted like long lost brothers. Neither one really did more or less than the other. The same thing will probably happen here since Fletchling and Hawlucha's battle styles, like Staraptor and Gliscor's, will be very different. Fletchling will obviously have Fire-type added to it, but it will probably be the main Flying-type Pokemon. Hawlucha could have a Flying-type move or two, but it will probably be treated like a Fighting-type more. It would be similar to Scraggy and Krookodile in BW as well. Both were Dark-types, but they used their Fighting and Ground-type aspects more, respectively.