First, I want to say, what type of game is it? That really changes the answers. What do you want your game to do? Who should play it?
For this, I'm going to assume D&D the way I most enjoy playing it.
Many dice is fine by me.
No. Stats are actually mostly legacy, and not good. You should be able to arrange things so that you only need 3 stats, and one is your focus.
Yes. See stats as legacy. I should be able to make the character I want to play.
This really depends on the genre. But hypothetically, I would say, classes should be what power sources in 4e should have been. A class should be Wizard, or Shadowcaster, but you should be able to make different kinds of Shadowcasters or Wizards, even some that do melee, or single target, or AoE, or damage or debuffs.
Well, as my above classes, you can't really be multiclassed, but as I said, it should be flexible in that class should not lock you into role.
Probably an existing world. But I would try to make it included in the core material, sort of like Greyhawk in D&D. Ideas about what kinds of things exist is good, specific places is not.
That would be fine by me. In fact, preferred.
Generally speaking I would be upset by any DRM of any kind because I don't like that **** on my computer. But I would be willing to make wide allowances based on how not intrusive it is.
Honestly, you should just build it as restrictions into the file if you can, not as actual running crap. If someone wants to crack your material a lot, they will, but if it requires even a modicum of programming that will stop all but the people who would also defeat your DRM.