THE THREE RULES OF GAME DESIGN
I. Start with Design Goals. These determine what you are trying to do.
II. Try to Impelement these Design Goals in your game, to the best of your ability.
III. The Design Goals are your determination for success. If you find that your rules don't hit your goals, adjust your rules until they do. If you find a goal to be untenable, or that once you hit the goal you don't like it, remove or adjust the goal.
This shapes what I think valid criticism is. You can either debate the validity of a Design Goal (should we have this design goal, shouldn't we?) or you can debate the validity of how it is implemented in the rules (There is a disconnect from what you are trying to do and what your system actually achieves). You cannot debate the end result without engaging the design goal.
But if the Rules match the Design Goals of the author, and you don't like the end result? That just means the game is trying to do something you aren't interested, and that is fine.
So, for example:
"I don't like how they gave Fighter's 'spells' in 4e" isn't valid.
"I don't like how they had a design goal to give fighters complex stuff to do" is perfectly valid. It engages the design goal level, and draws in to question the nature of that design goal.
"I don't like how fighters and wizards are balanced," is valid criticism; it might need some explanation, but it is engaging the design goal.
"I don't like how Fighter exploits use the same mechanic as other powers" is valid; it engages the execution of the rules.
So, in my playtests, I am going to be going in to detail on the rubric I set up before, and try to link things back to that.
I do think D&D is in a weird position, and that is why I flocked to AE and IH. D&D has to have a design goal of "Being Frickin' D&D." AE and IH could break free of that. 4e actually tried to in some ways.
4e is my favorite, and I agree with its design goals. But I can totally get that other people wanted different design goals.
That doesn't make me right and them wrong. It means we have different tastes, and I was kind of lucky.
But the fact is, I don't think that the game can be everything to everybody; I'm not sure that it should try.
But, enough of that. ON TO THE CAVES OF CHAOS!