"Scouts rely on stealth to survey routes and opponents, using ranged weapons and skirmish tactics when forced to fight. By contrast with barbarians, in combat scouts tend to be cautious and methodical, rather than impulsive." (Morrowind player's manual)

The Scout combines the best of all three classes. The skills in Medium Armor, Light Armor, Long Blade, and Block carry good advantages in combat; Alteration provides a good selection of very useful spell effects (including the ability to Open locks), and Sneak is a key Thieving skill. Were I to have designed the class, I might have swapped Medium Armor for Illusion in order to gain bonuses in Personality and enhance the ability to move around obstacles, but it's a good class.

Specialization Combat
Favored Attributes Speed, Endurance
Major Skills Sneak, Long Blade, Medium Armor, Athletics, Block
Minor Skills Marksman, Alchemy, Alteration, Light Armor, Unarmored
Starting Spells none

Combat Long Blade, Medium Armor, Athletics, Block
Magic Alchemy, Alteration, Unarmored
Stealth Sneak, Marksman, Light Armor

Strength Long Blade
Intelligence Alchemy
Willpower Alteration
Agility Block, Sneak, Marksman, Light Armor
Speed Athletics, Unarmored
Endurance Medium Armor