OS is hands-down an outstanding project. Even though I have played here just for 2 months on NonRR server before leaving it, it was still the best experience I had and no other server can compare with this. The reason I left was my mates stopped playing due to lack of PVP after GROM got banned and fact that many players got decked out in full ancient sets so fast .Few weeks after we left there was pvp-based update for events that got me really excited but unfortunately I decided to not come back because I felt I would not be able to catch up. I can honestly say I regret leaving this server and wanted to return when new non-rr server is released.
Regarding current Non-RR server it was great experience but it had some flaws for ''Hard-core'' server. I would like to point some of them out so maybe we can improve its next edition.
1) Gearing was too easy- There were some people who got decked out in full ancient set too fast even before stepping into Land of Trials. Some SM got Enis+Anubis in 2-3 days and solo-carried every event boss from then on so I guess ancient drop in DS was too high. You could farm Maya every day without any competition (pvp was dead there) and it dropped 3 top-tier weapons every day. It would make more sense if Maya was dropping 1 weapon, same for CW event where every Dark Elf monster could drop top weapon too was just too generous. Regarding IT it was heavily abused half of the time with anti-gaming and rewards (Flame/Feather of Condor) were too great. Just by entering event you had 50% chance to be winner and get reagents for 3rd level wings. I think Feathers for 3rd wings should only be made by players or given as rewards for big-events, regarding flames they can be farmed in Swamp with really-low drop chance. Last but not least is Blacksmith (+9 ---> +12) for credits. Whole upgrade system was turned up-side down to force people use credits for upgrading, because instead of chances decreasing the higher level item is, it was actually increasing, making +10 less success chance than +15. I understand you have to make money, but after few weeks of server release seeing people in +12 or even more on a hard-core server is just wrong. In addition Medals were dropping +11 items that many semi-active/casual players used for 1-1,5 months, I think making them drop max +9 would stimulate people to upgrade items to +11/+12 thus increasing these items value and also giving some micro-gear progression to work towards instead of equiping full +11 and forgetting about gear for a month. I also heard about people killing Cursed Dragon at night/morning and getting 3lvl Wings from OldBox+5, which is absurd.
2) Events/PvP- last PVP-event update was step in right direction, BUT I wish it was implemented at start or atleast earlier. It is impossible to take any boss and out-damage fully equiped Summoner, so the only way to not make it boring dps-race that you eventually gonna lose is to add PVP which brings tactical elements and strategies for fights. Some players with worse gear/lower level say that pvp events leave them no chances, BUT they have no chance to out-dps those players on KS race without pvp too. Also regarding bosses ( Golden Knights/ Great Golden Dragon) I think they should be harder to kill thus giving more time for players to contest/fight for them and make it challenging experience.
Everything I wrote is my personal opinion and vision how I see real ''Hard-core'' server. As always I wish you luck with upcoming projects and never stop improving!