(This is just my opinion)
The thing is, mechanically, TOS probably cannot have the similar feelings of playstyle and gameplay to RO. The two games are literally separated by the design such as, delays, skill mechanics, general stereotypes of the game, even controls and movement.
In RO, it is a freeworld, it is the game that doesn’t hold your hand AT ALL, you just create your character before they just throw you into the harsh world. The design is not overly complicated. Gameplay-wise, there are no trace of leveling quest or solid storyline, Graphic-wise, it is pretty simple, epic 2-almost-3D animations. You can just customize your own characters 360 degrees all around because of how the game is designed. There are thousands of builds, thousands ways to play.
In TOS, everything is a little bit more restricted. You follow the quests for levels (grinding is okay, but quests obviously give more exp), the skills are strictly limited for separate classes. The design is more complicated and free-form because you can jump, attack, and you can directly interact with the world around you such as rocks, hills, and especially the finding quests. The movements are slightly bit sluggish because the maps are much smaller, and it has to be made that way because of how the game is originally designed. The devs just can’t deliberately increase the map size because it will turn out to be too boring to just walk around.
Overall, TOS is designed to be a bit more solid form gameplay-wise, while RO is almost 100% free-form. What people tend to forget is that, this is Tree of Savior, not Ragnarok. Sure, the designer is the original designer of Ragnarok and many consider this game to be its successor, but in truth, Tree of Savior technically is not the successor of Ragnarok. It is a brand new game that implemented certain aspects of Ragnarok, but at the same time tries to introduce new game mechanics concepts to be differentiated.