Dissecting the 4e Fighter
The Fighter is the easiest of the iconic D&D classes to understand. He hits things hard and can take a lot of hits. His purpose is to engage opponents so they don't go after his squishier team mates and do as much damage as possible in the process.
Looking at a character in 4e, they are composed of their powers, feats, skills and class abilities. For Project 39, I plan on using the Star Wars Saga and Modern d20 system, where you use skills, feats and talents. As a character advances in a class, they gain talents on odd levels and feats on even levels. I'll still deciding on whether to use bonus feats versus general feats but the basic framework serves for now.
Another thing I have to look at is how multi-classing will work. I don't want to front load classes so that it is really advantageous to only take a level or two in several classes. This means defining class abilities in a way that will fit into my framework.
The 4e Fighter has Combat Challenge, Combat Superiority, and Fighter Weapon Talent. Fighter Weapon Talent just gives +1 to hit with either 1-handed or 2-handed melee weapons. Not really defining for a fighter. Combat Superiority is nice, it gives a bonus to opportunity attacks equal to the Wisdom modifier and stops the target if it hits and a move provoked the opportunity attack. This keeps those melee baddies from going after your wizard buddy hiding in back.
The last, Combat Challenge is what in a MMO would be called aggro management. It lets the fighter mark a target he attacks. If the marked target attacks anyone but the fighter, it has a -2 to hit penalty and if it shifts or or attacks someone other than the fighter, the fighter gets to make an immediate attack on it.
I'm thinking a talent tree (talents are grouped in trees) called Warrior's Challenge. Both Combat Challenge and Combat Superiority would be in that tree. They would be starting talents for a single-class fighter. Multi-class characters only get to choose 1 talent for 1st level in a new class, so they would have to decide which one they wanted, though I might make Combat Challenge a prerequisite for Combat Superiority.
My next step will to be to build out three or four talent trees with at least five talents each. The talent trees aren't linear, which means that in order to get Talent D you have to have A, B and C. However, C, D and E will have at least one prerequisite, meaning the best abilities are available only to those that invest more in the class.