I think melees are the easiest classes to play at low levels for absolute beginners. Fewer buttons to push, no sp management, fewer gear swaps. The way the game is designed just about any beginner can be a decent melee if they have a mobile auto-replenishing HP shrine with them (whether live player or hireling) up to a point.
Because soloing high-level elite content - even with a hireling - is very difficult.
Once a player learns the mechanics of the game, casters are actually the easiest class to play. Self-healing, burst dps, dots, AoEs, and a host of helpful utility spells make this game a cinch for casters to solo elite content.