The DnD Next blog post this week was light on details but still interesting. The main thrust of the article was that the designers built the game with a hierarchy in mind, specifically that some sorts of choices were meant to be more important than others. Class is the top of the heap and as such if a class does something then races, spells, feats, and backgrounds are never allowed to do that same thing better. In particular Mearls talks about how rogues are supposed to be good at stealth so spells are not allowed to make a wizard superior at stealth. In previous editions this was an issue because at high levels flying, invisible wizards with divination magic were drastically better at stealth than any rogue could ever be.
This strikes me as a good thing, particularly the emphasis on spells being worse than classes. Hopefully this will lead to casting classes generally being comparable to thugging classes in overall utility instead of being insanely overpowered at higher levels and rendering thugs obsolete. I would personally change my focus to 'spells shouldn't be as powerful as they were in 3rd edition' rather than specifically trying to avoid making spells more powerful than particular class features but I can't fault their goal. It is a tricky thing to accomplish in any event because classes have such varied abilities both in combat and out.
I have managed to avoid this sort of balance issue in Heroes By Trade by carefully separating out where character power comes from. Classes provide combat options and themes but they do not provide skills or other non combat abilities. This makes balancing them much easier as I just have to make sure Fireball is balanced against Cleave and I don't have to worry about balancing Whirlwind vs. Invisibility or Charge vs. Teleport. All characters have access to Rituals and Skills regardless of class so I don't have to worry that a particular class is going to be obsoleted.
There is a disadvantage to doing it my way though. Classes in DnD are very much full of lore and flavour. Rangers are good at tracking, Rogues at stealth, Bards at singing, etc. Classes in HBT have themes but lack the crunch to go with those themes. Marauders may be animalistic in their fighting style and Wizards may summon things to smite their enemies but those don't really translate to out of combat prowess. I did this deliberately because I wanted it to be possible to build a tough melee combatant who was good at magical theory or a spellslinger who was talented at athletics. When class choices specifically include crunchy noncombat options people end up playing the archetype instead of the character. That said there are surely many people who want every bow user to be called a Ranger and to be good at tracking either for lore or for simplicity.
The way I see it if people are very attached to Rangers being the best trackers then it doesn't matter much what my system is because they aren't going to like it. I feel that I should target those who are dissatisfied with the DnD model and want something different, something more. Rather than try to accommodate everyone I should instead figure out my own style and then execute that perfectly. There is already plenty of watered down mush out there.
If that wasn't enough then I can just go with my instincts. Making a product that tries to be everything to everybody makes me want to stick a fork in my eye. On the other hand making the best game for me sounds like a wonderful time so I suppose I should just do that. I have the luxury of not having a bunch of stockholders breathing down my neck and I can just do what makes me happy.