Character classes vs character types

 In Tunnels & Trolls Ken St. Andre decided against classes like OD&D had. Instead T&T has types, which aren't really specific professions but descriptors of broad kinds based on their relationship to magic. Whereas a cleric in D&D has specific encoding around pious warriors and undead hunters, anyone wanting to make a cleric in T&T could basically choose any type they want. A warrior type would be a non-healer, more like a Knights Templar. A rogue (who has some innate magical prowess) could be more like a priest with some spells (a Poor Baby, of course), while a wizard could easily be a divine monk with great magical abilities. 

The bonus of having a class is that you know what you're going to be doing - particularly in later editions where you're set into boxes. There's also no reason you can't play around with thematics. Earlier editions were more flexible this way while later editions would have so many extra rules and abilities that they became much more rigid. 

I enjoy both methods, but sway towards T&T's broad types. Later they would feature specialists, which is as close to classes as they ever got, but still broad. There was a great article in one of the Sorcerer's Apprentice magazines where Ken took inspiration from Arduin, helping readers create traders, assassins and others. Similarly there was a Trollszine article that explained how versatile the types system is, creating shamans, thieves and the like with just the types and stats available.