Ty all, I think I'll play IV and VI now then
Some general advices:
If you play someday Dragon Quest IX, invest your skill points directly to the job's skill tree (and later, choose wisely your weapon of choice). Seeds are quite a trick to get.
The game is like Dragon Quest II:
At the least, unbalanced. So, it is critical to have a Priest in your team or someone who can cure enough HP...
Or a Gladiator (mix it with a Falcon Blade and you will see).
Try to make a balance, when you choose a party and when you change jobs. And don't overlevel so much (in case you want to fight the 12 grotto bosses, they are optional, but have a specific order, regarding the level of your main character.
Yes the last one is possible, without finishing the game, believe or not).
Try to take your time, gathering resources, getting enough money and the necessary equipment, for Alchemy.
Specially when you are reaching End-Game and Post-Game.
The choice is yours!
Some weapons, are extremely good, for specifical effects or properties!
Like the Falcon Blade or the Demon Spear, with the right skills...
(The Demon Spear can kill sometimes Metal Slimes and its variants)
Do you want a funny way to defeat enemies?
Don't overstimate the power of "Have a Ball" Skill (looks strength-based and can surprise you).
(Feels like The Joker, launching stuff with a party/toy gatling gun, just saying)
If you try to go a grotto, blue chests may differ in content.
Don't think about its content, because is a special mechanic, like a Roulette.
There are Ranks about this...
Same for monster in grottoes, like a hierarchy system.
All calculated, via your main character's level.
If a Point of No Return happens, I recommend to take your time with the Bestiary to hunt... And its Drops.
Trust me, it is a pain, but for the better avoiding future headaches.