You haven't played rust have you?
Off the top of my head here is some of the game changing things you can add:
full craft to instant craft
Starting with nothing to starting with full kev/m4 (changes if you are a hard core pvp or a survival server)
Kits from a revolver and beans to a bolt action and .556 ammo
Econ plugins to make useless items like paper and stones be used to buy items using /Buy command.
Events that happen such as full out pvp arenas
Air drops
Sleepers or no sleepers
Length of days/nights
Auctions/Banking
Doorsharing
Removal tools
Compasses
Resource bays
Crafting denies/Allows
No decay/decay
Locked back packs and set time/No locks
No durability/Items degrade
Bounties
Oxide or Rust++
There are many more mods/changes that an admin can make the server to attract the type of players he is looking for. Rust is created by the same guys who made Garry's mod so you can expect a large modding community to group around this.
As for choosing what game server that should be made is really all up to the staff that can dedicate time to it. As a server without active staff is clearly bound to fail. BUT.. choosing an old, already over used game that has an already maxed population that will not grow any longer and that can only shrink makes no sense to me. Rust is the newest and latest thing that is still in early alpha, This is where I believe time should be spent as this game will only go up from here not down. This is the next minecraft, this is where the next modding community will grow. There hasn't been a game in a long time to have such sales/fan base in this early of alpha in a long time. Rust is where money should be spent and where time should be invested.
Stop setting goals on mediocrity And go big guys.