I don't know how much it would help, but maybe your new job trainer(s) could be introduced to you at the end of the class questline. Adjust it so the job quest flag isn't with the job trainer, but with the guildmaster. You accept his quest(s) and run off to the job trainer. You then see a red triangle above the job trainer's head. You talk to the trainer and get told that you must be at least level 30 MRD and 15 GLA to continue the quest.

That way it gets your attention right away when you complete your final class quest, and you're able to learn enough of what you should do to continue.