I've managed to get PlayOnLinux to work minus some few weird things here and there. Using 1.7.55 on a 32 bit wine prefix should work. A few things to note are to use "Emulate Virtual Desktop" in the configuration, then use use TitanRO's OpenSetup to set it to that resolution and enable fullscreen to simulate a pseudo windowed mode. I've tested the DLLs listed in Sam's guide extensively, both by installing it through winetricks exclusively, installing the POL components that match exclusively and mix&matching but I didn't see much difference compared to before I installed them.
Some few problems I've encountered so far:
Messed up fonts
As in no anti-alisiasing and sometimes just straight up boxes in place of letters. You can still read all the things that matter and you get used to it eventually but it's there. I've tried using POL's microsoft fonts, which slightly makes it better but not really, and winetrick's does the same but never really solves it. Recently though I've been thinking it might be caused by my fontconfig so I'm not sure.
Progressively increasing stuttering everytime you move maps
Yep, not sure why it's happening yet. Everytime I move maps, it's like frame rate drops and it sticks. When I first start the client it's silky smooth like I've never played Ragnarok this smooth. A couple of map changes and the client goes into this nauseating stuttering mode. I have to restart the client. Simply doing character select doesn't work. Most of the time it's fine since I stay on the same map to grind so I just have to restart when I enter that map and I can stay there for a long time with no frame drop. But when doing quests where you enter/exit lots of buildings and maps and warp lots of times, it's annoying. Fly wing doesn't seem to affect this so it's not too bad.
No RODEX Panel
I just noticed this recently but apparently everyone has a RODEX panel. I don't. The arrow under the info window doesn't appear. Not sure what I'm missing.
So far that's all the isues I've encountered. If the client doesn't run on PlayOnLinux, you'll have to open Debug and see the errors it's spitting out. Usually you'll just have to install some 32bit libraries here and there to get them sorted out. Another is if the debug outputs something about Freetype2, you'll have to delete the libz*.so files in $HOME/.PlayOnLinux/wine/linux-x86/1.7.55/lib.