Firerwork ninjas don't change a thing. Maybe with exception of AOG Konan (if someone managed to complete her later) and Jonin Minato (if you can unlock his Bond Mystery). Third Raikage, Samehada Kisame, Swimsuit Merui or Dan change nothing against old servers where even f2p players are using Habanero Kushina - Kotoamatsukami Shisui combo.

What Oasis should do is review and update some prices, at least for younger servers. 14k coupons to get Hokage Minato from Treasure of the Sage is unfunny joke.