Low Dexterity
The arcane warrior immediately starts with a feat to use his magic statistic to apply to weapon and armor requirements, which eliminates the need to sink points into the strength statistic. Unfortunately, the same does not apply to your low dexterity, which is a crucial element in determining your accuracy in combat. As a result, you may need to spend a few points on dexterity to achieve consistent hits.
Mana Management
Be prepared to spend a lot of time upgrading your willpower. In general, the arcane warrior specializes in steady buffs (for weapon and armor enhancements, for example) as opposed to casting repeated spell attacks. In turn, the character's mana remains at a fairly consistent low level that allows for very few spells to be cast in the middle of combat. A higher willpower stat can alleviate some of this issue by giving you a greater mana pool.
Useless Skills
The only skill that truly benefits the arcane warrior is combat training, which can give you greater poise for resisting falls and spell interruptions when you are attacked. Trap-making, poison-making, herbalism, stealing and survival all rely on attributes that should not be a focus of the arcane warrior class. Luckily, you can attune your skills to your original class or your second specialization.
Overall Gameplay
The biggest difficulty facing arcane warriors is the fact that they don't achieve the full benefits of either mages or warriors. High-level spells are generally out of reach unless the player is spending nearly all of their attribute points in magic, and powerful weaponry is accessible but the player will miss more often than warriors who can balance their points between strength and dexterity. Compensate by selecting a second specialization that allows benefits or new spells to cover your weaknesses.