@Solwern It doesn't look natural enough. There is something VERY important you need to learn early on, and that's the 3 tile rule (suggestion). Never put three of the same exact tiles right next to each other in a straight line. You gotta' have curves, just like nature. Of course, there are obvious exceptions to this rule, like when you have man-made structures like roads. Those should be as straight and to the point as possible. But when making cliffs, or nature paths, or forest openings, they need to be less perfect. The section in the top left of your forest map illustrates this pretty well. I'd like to see the whole map looking like that! I do like how you have decided to use normal trees instead of the tree wall tile, I've never been a big fan of that thing.
The first map has some good randomicity, but it's a little too spread out in my opinion. Try layering some trees over one another and putting clusters of flowers and bushes together. I would also apply the 3 tile rule to this map as well, make sure you cliffs are curvy. The grass here looks fairly good, though.
Just like Hex said, I would try to make them smaller. The only way your player is going to enjoy playing your game if the maps are this big is if you have LOTS of stuff to do in them. And not just random encounters. Secrets, treasure, NPCs, wildlife, enemies on the maps themselves, etc. If you can't make a game with that much stuff to do I would heavily advise cutting down on the size of these maps dramatically, or at least splitting them up into multiple maps. It could cause lag too, so just be aware of that.
Here is a map I posted on my profile already, but people seem to like it so I figured I would post it here too. It's a mountain map I worked on for at least 15 hours. It leads up to a volcano (of which I've posted some screenshots before), and the path up top leads to a resort in the mountains further up. I haven't added any events yet, but there will be treasure, and enemies (since we're going for a Super Mario RPG-type approach on those).
I'm thinking of changing the bridge to something else to enter the volcano. Someone was banished there long ago and I'm not exactly sure there would be a bridge just going straight into it. Any ideas?