My longer term ambition is to improve the history section in the Wales page, and the 19th and 20th century sections in the History of Wales article. At present the former manages to go from Medieval Wales to the Nationalist Revival, with barely a mention of the profound changes that took place in the intervening 400 or so years. The latter, meanwhile, almost completely neglects the impact of the wider Labour movement or nonconformism on Wales.
Wikipedia comes in for a lot of criticism but I use it as a reliable resource nearly every day and the process of collaboration, while frustrating at times, is in itself a hugely valuable activity.