Being the huge F & F fan that I am.. I have to stick up for the series a little bit.
Dom fought all his life. It's not unreasonable to think he could kick someone's ass in a fist fight. But his accuracy with weapons? Yeah, that's suspect.
Brian was an FBI agent. He at least had training.
Tyrese grew up in and out of prison and shyt. He must have known how to fight.
Ludacris character did seem to change as the series has gone on. I don't remember him being a tech/computer/etc expert until maybe Fast Five.
In 2 fast he was all about collecting and organizing