I never played Dragon Quest, outside of one of the GBA games I believe (or DS, can't remember... it wasn't the actual RPG one I think), so explain?
Dragon Quest 3 had one of the most groundbreaking and innovating job systems of all time. You are able to create party members (other than the Hero) at the first town from the classes of Soldier, Fighter (this is like a Monk), Wizard, Pilgrim (this is like a Cleric), Goof-Off (more on him in a moment), Merchant, and in updated versions Thief. This was a huge enough deal at the time, but it gets better.
When you reach the Dhama Shrine you are able to change classes and for anyone who reached level 20+ you get to keep the abilities you learned along the way. By doing this you could create a something along the lines of a Paladin by having a Pilgrim reach level 20+ then change him into a Soldier so that you have a full plate mail wearing warrior who can also cast divine magic. You could create something similar to a Red Mage by having a level 20+ Wizard change into a Pilgrim so he can begin adding divine magic alongside his offensive spellbook. Lastly.... the seemingly useless Goof-Off class at level 20 can become a Sage which is what every Red Mage wishes he was, the Sage learns EVERY divine and EVERY offensive spell. You retained stat bumps from your previous classes. You could create a Wizard with a higher Health Point count and better base attack bonus this way too by changing a Soldier or Fighter into a Wizard.
Now, here's the kicker. This game in its original form was released on the NES in 1988. This game was ahead of its time.
I recommend honestly the entire series. 4 is my personal favorite, being the most traditional of the bunch. It does not have 3's brilliant job system but it has a great cast who each bring something different to the table such as in the older FF games. 6 is the medium between these two extremes having a very similar job system to use by a cast almost as memorable as 4's. 8 is also very popular, it was the one to finally take the series out of the classic visual style. 2 is so hard it's legitimately unfair towards the end, but if you want the challenge try that one too. 5 has the best story, and a lot of replay value because you pick a wife for the hero so it's fun to play through seeing what families with each love interest are like. 7 is another I look back fondly on but it's LONG.... I clocked in over 250+ hours on that game.
I'm still thinking on the rest of your question. I'll try to have an answer tonight or tomorrow.