I don't know how to make suggestions for Ragnarok.
First of all I want to say WoW! just such great work! I had some ideas if not thought of I think would be great to add to under development section.
1. A crater Biome. Not a volcano one but an impact crater. Possibly in your Desert or it could be a bay with edges that clearly look burned out. Lake Tahoe, Crater Lake, Southern Arizona are all great examples.
2. Would love some volcanic plateaus too. See Sierra Mountains around Sonora for examples, or Southern Utah.
3. White Cliffs of England on your Scottland Zone.
4. Geysers, OMG no one has done the sulfur exposed blue pools yet in their maps. Lets get some Caldera action going.
5. South East Asia island system where you got old crags coming out of the water with jungles on top. Leads into some canyons and other Jungle systems.
6. Bamboo Forest - probably limited to Devs of game at moment.
7. If they ever add disasters or weather systems like tornados, then a dirt devil would look sweet in your deserts.
That's about all I can think of at the moment. None of it you have to do, but wanted to throw my two cents out in case you have some ideas of your areas but some things are still in brain storm. Love what you have done and look forward to seeing what you got cooked up for the rest of the map.