Yes, the game is worth of your money even if you will be both pleased and dissapointed
Yes, you can create your own class in Morrowind
but your possibilities aren't so extensive as in Daggerfall. Nevertheless, you can create a class which will fit your play style.
Yes, you can create custom spells and custom enchanted items in Morrowind
but the spells are even more overpriced (as far as spell points are concerned) than in Daggerfall. Nevertheless, you can become a strong spellcaster.
Moreover there is alchemy in Morrowind, you can create custom potions. Naturally, graphics is something very different from Daggerfall. Add a very nice storyline, many quests, and character development during the game and you get Morrowind.