I actually wonder if it would be better if we had a team of writers rather than having a single show runner. I understand that the former could have its share of problems due to conflicting ideas and vision, but getting a bunch of talented writers together to share ideas and call each other out on areas that don't work would be handy. Then maybe we would have less endings like Series 3 and 6. I'd like to include Series 4 somewhat as well since the ending was probably the worst moment in an otherwise excellent series.
Edit: And can I add how utterly disappointed I was with Let's Kill Hitler as a missed opportunity for Who to cover
Hitler's Time Travel Exemption Act? I mean an episode where the Doctor has to keep one of, if not the, most hated people in history alive to ensure that time not be irreparably altered just seems like a better plot than... shoving him in a cupboard five minutes in and forgetting about him. Maybe an episode dealing with such questionable subject matter would be too edgy for a "family" show though.
I also rather hoped that River's hints to being put away for killing the greatest man she ever knew would mean that her last episode (the first from her point of view) would be her killing the Doctor and gifting him the rest of her regenerations as a way of ending her character arc and also solving the regenerations issue.