Here are my reasons:
Warrior and Ranger are both known for their strenght and armour so having a good strong primary is a must imo. However i have chosen to go with ranger, because he can attack form a distance whereas a warrior is best suited at close combat. Also rabger can summon a pet. So theoretically ranger and warrior are similar in strenght but ranger gets a few bonuses: attack form distance and a pet.
Same with monk and say a elementalist or necro.
Monk has some good attack and damage spells, but unlike E and N he can also heal as a bonus. Three of these classes can attack, yes, but monk, as a bonus can also heal, so why not go monk?
So now you see my question, hopefully. Is my theorie somewhat correct? With the few bonuses i have listed. I see these 2 characters as similar to others but they can summon a pet and heal as a bonus.
ANY commnets would be greatly appreciated be they negative or positive or random, i really want to know what GW experts think here
