While designing Heroes By Trade I attempted to build a skills based system (as opposed to a level based system) that had reasonable combat balance. Normally systems that are skills based let characters improve any part of their character and that inevitably ends up with the twink standard - Either you twink out for combat as hard as the biggest twink around or you are useless. You can, of course, be good at other things but I never much liked that dichotomy and the endless complaints about how Rogues are garbage in DnD show that a lot of people agree with me. The majority of people want a game where everybody's contributions are different but where everyone feels effective and useful. When people watch The Lord of the Rings they don't mind heinous imbalance (compare Legolas to Pippin!) but they don't like it when they have to play Pippin themselves.
Given that I decided that I need a level system to regulate character power but I wanted it to be extremely simple to use. When you gain a level you add one point to an Aspect (Strength, Dexterity, Constitution, Intelligence, Willpower, Presence) alternating between physical and mental stats. This ensures that overall combat prowess is very tightly controlled. The second benefit of gaining a level is that you either learn a new combat Power, a magical Ritual, or a Skill. Gaining flexibility has substantial diminishing returns so although people have immense freedom to customize their characters they really can't break the balance of the game significantly. The other nice thing is that every time a level is gained people get to do one thing to get more raw power and one thing to learn new stuff. Hopefully this satisfies both the power gamers and the people more interested in flavour and cool stuff.
Sadly DnD Next is looking very silly indeed when it comes to the leveling system. For all of the thug classes there are plenty of levels that do absolutely nothing in the early going and the levels past 10 are much worse. The Fighter, for example, gets a new daily power at level 11 and then all the way up to level 20 the only thing they get is more uses of that power. No choices, no feats, nothing. Just increase a number like the chart says, or maybe don't even do that. Levels 15 and 16 literally have no effect aside from rolling for Hit Points! I would have thought that the designers were aware that people didn't like classes being divided into "Cool new stuff all the time!" and "Nothing to see here." It isn't even a matter of balance as honestly the thugs look very scary at high levels and it seems like a regular attack from a fighter is probably as deadly as a Disintegrate spell. It is just *boring*.