Which is precisely the point. I see no way of exciting creativity when the level of variation drowns out individual effort by the less creative and requires minimum exercise by the super-talented. However, you are correct that what I outlined is not enough to inspire.
Two people join a class, one from a poor school and is a ways behind, the other spent time in a crammer and is functionally a year ahead. The first person learns a lot more than average, but makes only an average grade. The second person does nothing but play games on their phone, but knows all the material and gets the absolute maximum grade with all the bonuses.
Clearly, the first is making the best use of resources and is highly adaptive. The hallmarks of intelligence and creativity. The second was able to learn fast, but they're a one-trick pony.
Putting these in the same class will dispirit the first, as they will remain invisible, but encourage the second because they're a superstar.
My approach is to say that years are an illusion. You start at a given point on the continuum, you proceed at your natural rate and in your natural style. If you can learn fast, then learn fast. If you can learn deep, learn deep. If instead of learning isolated facts, you can discover underlying patterns never seen before and interpolate the facts correctly, then do that instead.
A test for any one of these, or geared in their direction, will be failed by the others.
What is the purpose of testing? In the real world, mostly school PR and student PR, standardized tests have no functional worth. In my imagined school, it fine-tunes the experience, each student gets a completely customized schooling based on where they are and what they can do.
But this gets back to your point. That, alone, is not enough. It removes friction and inaccurate perceptions of failure, but where is the inspiration? In part, it would come from teachers/lecturers who aren't trying to deal with all types but know exactly what the score is. In part, it would come from the flexibility produced, allowing projects and contests designed with the students in mind and not diluted to cope with other types of mind.
There may need to be more besides. I am not sure yet. These 15 streams would diverge, never to reconverge. Creatives create, thinkers think, creative thinkers creatively think, and nobody gets in anyone's way.
People should have a broad enough base that they have a real, meaningful, functional choice of careers.
People should have enough research skills that they can realistically switch career paths midstream.
People should have the deepest knowledge in each field that the above constraints permit.
People should develop their own methods of learning, memorizing and understanding, so as to maximize all three.
People should never be satisfied with the old for being old, or the new for being new - age is not an interesting property.
People should invent what they lack, if they can, or request it of those that can.
Meeting these constraints is hard, and there are probably many I am missing. But, as you can see, my idea is very different from any existing system.
The objectives are to increase personal freedom to make use of talent, better meshing with less office politics between different people (nobody needs to feel threatened, because cogs don't get replaced by axles - even the perception of a threat is reduced), less friction and more traction in the arts and sciences, more real progress and less smoke-and-mirrors illusions of progress.
Well, those are the primary objectives.
The secondary ones are a superior match to Plato's requirement for functioning democracy, the tackling of issues rather than assuming they are too hard to solve, and the closest approximations yet to Homo Universalis, as determined in the Renaissance to be the ideal due to the interconnectedness of life. (ie: Because all the sciences make reference to all the other sciences, you can only partially understand a science in isolation. To completely, 100%, understand anything in all aspects and at all levels requires that you understand everything. This is impossibl, but how much to learn? Pick the must-haves, then maximize across them. It's about all you can do.)