I would add some supports to that building (under it), and remove that random candle. I've never really liked those trees, nor can I make them, but I guess that's more of a personal preference. It does seem a little empty though marshes would have a little more wild nature, and I am speaking about the place you focused on not the surrounding areas. It will probably end up as a good piece when you finish it. Oh and p.s. most mapping is time consuming it's a part of the job, haha.