No problem and there isn't really any "critical" characters but if I had to list a couple that were the most worth springing for because they bring a unique kit or blow out the competition, it'd be Rikku and Ayaka. Although CG Fina will join Ayaka's club, eventually. Unit's like Orlandeu and Veritas of the Dark are amazing units but the thing is there are a small handful of units in their league that are all top tier DPS. You can get those two, Tidus, Aileen, etc. and be well off in that requirement for the team. That's why I didn't bother with landeu when he had an atrocious banner, Tidus is right there with him and was coming with Rikku so I was patient and regret nothing. Rikku is really unique with what she brings to the table, at least all rolled into one package and Ayaka just blows every healer out of the water until CG Fina. Those are the type of units truly worth splurging on IMO. Obviously if you're in a situation where you don't have a great DPS, Tank, etc. then it makes sense to go hard on a banner with great units fulfilling those roles but once you have a solid team, go for the value. Or splurge on every banner if that's how you have fun, we all should play how we like, this is simply my two cents.
