1. I would like to see quests, especially the main quest, where choices must be made and the choice taken has ramifications. This could lead to 2 or more different endings, which would enhance the replay value. Not something as trite as good verses evil, but perhaps the opportunity to take sides; as in Gothic 3 where you could join the rebels, the orcs, or even the druids.
2. Novel and chained side quests (such as the Gervasius quests in Nehrim). I know most quests ultimately boil down to get something or kill something, but those can be presented in interesting ways. Guilds are not necessary for giving quests, but similar results can be generated in creative ways; I especially liked the "faction" quests in Reckoning:Amalur, such as the House of Ballads series of quests. I especially did not like the "guilds" in Skyrim, such as the assassins guild where it was just one killing after another with no reasoning or story ("just go kill "x" and don't ask why"). Reward long chained quests with something useful such as some permanent ability/skill/stat increase, not just some shiny trinket to be sold.
3. Make all dungeons/caves/inns, etc. unique. You went a long way towards this in Nehrim, but there still were some repetitive dungeons.
4. If there are horses (or other animals !!) to ride, use the same controls as for the character. That worked very smoothly in Sacred 2 (where they had some really interesting rides!)
5. Darlan castle had some nice display cases for weapons, but what about armor. You see armor all over castles, how about creating some mannequins or frames where we can display all those sets of armor that we never use. Maybe even the possibility of opening a museum in some city for all the stuff we never use but still want to keep?
6. I would like to put more than 1 enchantment/gem/rune or whatever on a weapon or piece of armor. Maybe that could depend on quality; for example, 1 enchant on a copper ring, 2 on a silver ring, or 3 on a gold ring.
7. Please make the land wide open. I liked being able to go anywhere I wanted in Gothic 3, Oblivion, & Skyrim. I got frustrated that I couldn't go to Southrealm in Nehrim until late in the game (until I found a way over the mountains).
8. Please keep the ability to jump/climb everywhere. I enjoyed climbing to the remote mountain tops and ridges, just to see if I could. Of course, in Nehrim they were all barren. It would be nice to find some rare plant or animal skin as a reward for exploring the most difficult places.
9. I disagree with previous comments about having big, massive cities. Erothin was certainly big enough. Even during my 5th playthrough, I was still finding new places there. We don't need another Dragon Age 2! Devote those resources to more locales, dungeons, hot springs where I can heal/cure, maybe a ski jump?, or whatever. I also don't want big battles. Use the resources for places to explore, that is what an RPG is all about for me. I think big battles would just devolve the game into a common hack & slash/shooter type game; no thanks!
10. Don't get carried away with magic. Magic effects & displays seem to be one area where it is easy to overload a computer that isn't top-notch, state-of-the-art. Not everyone buys a new rig every 6 months! And don't get too cute, like anvils falling from the sky (Two Worlds 2), or too overpowering (such as the meteor shower in Reckoning:Amalur that kills all enemies around you but doesn't harm a hair on allies or friendly NPCs).
11. English voices would be nice, but I understand why that might not be feasible. I can live with English subtitles, but please translate all the letters,documents, etc. It was frustrating in Nehrim that, even after the last patch, I would find notes or letters in German and wonder if they were telling something I needed to know.
12. Don't make the physical puzzles too hard. In Nehrim, I could never complete the quest to move the black powder barrels from the fire and had to use the console to advance the stage. I did manage, after many, many deaths, the jumps across moving platforms, but they stressed me. Remember, some of us are old folks with slow reflexes.
13. Don't feel it is necessary to put something in every box/crate/barrel. I would rather find most of them empty, than finding useless, valueless stuff everywhere such as clay bowls, forks, etc.
14. All components of the same description should match. For example, I gained several "wolf pelts" from different types of wolves, but even though they were all described as a "wolf pelt", many could not be used to make the armor requiring wolf pelts. Very frustrating.
15. I prefer fast/instant travel to already-discovered locations, by clicking on the location on a map, rather than the teleport system used in Nehrim. I was frustrated at much time wasted traveling the same trails repeatedly to reach certain locations without a teleportal, such as Treomar and Southfield.