First off, I think sometimes people overthink when deciding required systems. Everyone does? But, what is the main goal? I think that is the question server owners new and old should be asking. It's one thing to throw a bunch of systems together (most servers do) and it's a completely other thing when deciding what systems are meant for the server you're planning (not many people). People forget that there's a balancing act with systems and gameplay design and only consider balancing as what class does how much damage. It's why, in my opinion, most flyff servers suck now. Essentially, you could argue for any system or argue against any system.
Simple example:
I disagree with 4 from mew5151515 and the reason behind that is I believe that costumes shouldn't be upgraded nor awaked nor have set effects. This also solves the issue with not being able to get stats on old fashion and also keeps fashion items as just fashion rather than some way to increment or over fluctuate a user's stats.
Then again, maybe the server they want (Just using as an example, I don't know what they want) is more towards balance through overpoweredness. There are many servers where you get 500+ stat points on items and high awake, and it's a one shot fiesta and the dungeons are just AFK and sleep through. Very pointless and dulling)