What I'd propose is actually giving replacement skills for Marksman/Scoundrels because they're unimaginative as hell.
However, Marksman skill set definitely includes their Special Arrows so perhaps people who think they're so limited need to understand that having SPECIAL arrows is part of the kit's arsenal and not just spam active skills. These arrows have no cooldown either, a fine tradeoff for its limited quantity.
Scoundrel on the other hands seem to stop gaining new skill at end game. Kinda disappointing - I was looking forward to more trickery, but it seems possible the rogue class is meant to be a hybrid and not just a one stat end all type.