Here are a few more suggestions,
The top 3 winners could get extra coins/server.money, the option to edit the amount would be cool too
The option to turn off variables in chat such as $name (people use it to scam for gold and it can get annoying) this would be VERY cool to have.
setlava reloadlevels (player experience and levels in the new .txt file!)
Maybe /tcolor should be added to shops too since there's already title and color (I know smart ppl can use title and color chat to do this anyway, but ppl would buy this still)
A switch for random starting lava block type would be cool
Prevention to stop people with the same ip paying each other (to stop ppl using several logins to cheat ranks) this has happened a couple times since all you have to do is survive to get coins and then on all the different players the guy payed one character and got high rank very fast
(Mainly the in chat variables tho... this would be so good to turn off sometimes it can get so annoying)