Leveling up testing is relatively long indeed. I have to make sure that the gap between two area enemy strenght vs the amount of experience/gold given ration is good. This game is aimed to be easy in terms of leveling up, but you won't just be going straight through every area and dungeons, beating the boss then immediately moving on to another area without waiting in the previous one to level up. You will still have to stop for a short while sometimes to raise your stats, else at one point you might end up with nearly impossible to beat monsters. You also need to raise your magic levels as much as you can if you plan to mostly rely on magic in the game.
Leveling up gets much faster after you return on planet Illusiat during the story, though, but that's because after you reach LV 50 or so, each level ups doesn't have as much of a signifiant impact as it did early in the game. The only big impact it has is the HP increase.
For individual stat increases, you got to keep some gold to increase them more in shops sometimes. You can increase whatever you want, but keep in mind it's very expensive so you might want to save some gold to buy some magic, especially healing magic.
If I add a Hard Mode in the game, which would be unlockable after you beaten the entire game, enemies and bosses would give twice less experience and gold pieces and you would only be able to save your game in areas with no random enemy encounters
