It was actually pretty easy with SMN because you had to start from the beginning back then.
You started with Ruin, then to Bio, then to Miasma, Bane, then Golden Carby, then another Bio then another Miasma, then Ruin 2 (insta cast), Pet commands, you didn't get the Enkindles until 50th so it didn't come for a while. It just didn't tell you all the Bios and all the Miasmas stacked. So you had to figure that out for yourself. I seem to remember there being 3 Miasmas (one was an AoE), and 2 Bios, and then you'd use Bane to spread them in an AoE.
You also had to use the Contagion from Garuda once you went SMN so that it would extend the duration and you didn't have to keep spamming 5 different Poison DoTs each with a different duration and constantly keep tabs on the timers. That was the hard part. Figuring out how they all fit together though was pretty easy. Eventually they added Dreadwyrm past 50th, but they show you how to use it in the Quest Line. The only thing they didn't tell you was to make sure you use the controls on Egis as little as humanly possible or you'd regret it.
The wonky one was RDM when it first came out, because that one doesn't even show you the basics like BLM did.
So I remember taking up the class and going ok... so supposedly this job double casts. *casts Verthunder*
OMG this takes forever to cast, then casting it a second time right afterwords, like a dual Verthunder, or a Veraero afterwards thinking OMG this is wayyyy too long of an initial cast time.
Well this Jolt one is pretty fast maybe if I use that one first it will work.... yup, guess that's how you do it. (Not exactly intuitive, but doable)
Then I decided... ok well it looks like the Red Button is the first one you use... so... lets try the AoEs now...
*casts Scatter*....
Huh? Why is this taking so damn long to cast!
*Clicks Verthunder2*
Well that was fast... wait... wtf? This one is completely backwards... you do the opposite for this one?
The first version was Jolt to start it off... the AoEs you do the complete opposite and start with the Verthunder first... then close with Scatter?
Who thought that a good idea?
I don't know if it's better these days... but back then it was just a lot of... ???... and that was before you even got into the more complex stuff like putting all the other things together in a coherant whole.