Im not exactly a veteran but im a returning player, hopefully i can help bring back more people.
1. The feature i always wanted to see implemented is ranged combat. Its not essential to anything in the game and would need some adjustments elsewhere like boulder "immunity" or maybe tribe immunity but i know there is a lot of people like me who just like bows
To reply to MrDDT, i think a tutorial would help alot of people who are new to sandboxes and in any case new to this game. Hopefully it would be on a separate tutorial server where people could even test out terraforming and very basic building (like one wall).
Infested areas is a good idea, especially if its roaming around like other creatures. A pack of giant mutant wolves going from area to area periodically or revenants turning to highway bandits from time to time could add to the challenge, make it a "special" event and would force group play because of the number of creatures.
2. What made me come back to Xsyon is the freedom of a real sandbox, the dream of building a safe and somehow magical place in the devasted land and and the nice community. After a couple months in a troll and "raging nerd" infested game, i find it so relaxing and enjoyable.
3. What made me the most happy when i came back was the creature population patch. Fighting animals is much more accessible, you can find animals, you can catch up to running animals and you can kill lots of them. (Now because MrDDT showed me what was wrong with my swing its almost too easy though, but thanks alot still for the deer bones i can now collect at will)
4. Of course its too slow but i like the fact that it is in development and that players will enjoy new crafts, features and areas. Xsyon is a living and growing game.
5. Dont know about the active population since im soloing but there are 3 new homesteads in my immediate vecinity since i planted my totem, always new people in global too and tons more members on the forums (i wish they would speak out more).
My first major things prevent me to log-in. One, lack of PVE server. Two, soft- cap is way too low for skills and attributes, I would be ok if soft-cap don't drop below 75, it's not top tier but give's you something to achieve/work for. Three, lack of ranged combat. These are the main reasons for me not to log in. Other things I can wait along.