1) Why become a Wizard?
Wizards is the hardest hitting magical damage class in the game, and eventually will become the hardest hitting class in both the Physical and Magical damage realm. Not only do they hit very hard, but they're capable of destroying a massive group of enemies of equal level with a single spell. Wizard is also a ranged class, which allows for preemptive strikes at a distance and is very capable of annihilating monsters before they have a chance to approach, cast, or shoot you. Wizards are also one of fastest classes to conquer quests, making the experience grinding experience a bit easier to take in. Wizards are also the most diverse class in the game, allowing for more strategies available and also making this class one of the most difficult to truly master. A master Wizard can and will become a master of any other class if the player so decides.
2) I'm afraid I might create a failure, how do I prevent this?
There are common functional builds and abstract builds. The more common builds are the Pure Magic build and the Light Armor build. The more abstract builds are the Hybrid and Balanced builds. As long as most of your stat point distribution goes to Magic, you should not have too much difficulty coping with the game. What you should watch out for is leveling and acquiring skills you don't really need and not have enough points to use later on.
3) Type of Wizard Builds and Point Distribution
Rating System: 1 being lowest, 5 being highest.
Pure Magic build: Attack Rating - 5, Defense Rating - 2
Every Two Levels
Magic 9 Points
Strength 1 Point
Hybrid Build: Attack Rating - 4, Defense Rating - 3
Every Two Levels
Magic 7 Points
Vitality 2 Points
Strength 1 Point
Light Armor Build: Attack Rating - 4, Defense Rating - 4
Every Level
Magic 3 Points
Dexterity 1 Point
Strength 1 Point
Balanced Build: Attack Rating - 2, Defense Rating - 5
Every Level
Magic 2 Points
Vitality 1 Point
Dexterity 1 Point
Strength 1 Point
These are listed in terms of attack power. Each one of these has it's own strengths and weaknesses with its own uses and its own strategies. The further down the list you go, the more strategies become available, but the less damage you can do. It is highly recommended to decide between Pure Magic and Light Armor, but it is still a subjective matter.