A Roth IRA could make absolutely sense, but there are a few things to consider. 1. There are phaseout limits. So not everybody would be eligible to contribute. With the 529 plans, this would not apply. Addressing your points:
a. Absolutely right.
b. Correct, but earnings that are pulled out for qualified educational expenses will be taxed, just not penalized
c. Very True
d. The contributions can be taken out at any time, and are not subject to the 5 year rule. That just applies to the earnings. Those then fall under what I stated in b.
e. That’s one benefit of the Roth. If your kids don’t use it for school, at least now you can a tax free nest egg waiting for you at retirement.

The 529 plan does need some work. Personally, I would like to see a universal account just as the Roth IRA.

There are good 529 plans, you just have to do your research. And contributions to 529’s are rather simple. Coverdell ESA’s have more income restrictions.

Traditional IRA can also be used for education before age 59.5 years old.

529 is a law to create more investment products rather than helping financing education. Most 529 programs have poor returns. All these 529, Education IRA, etc are cumbersome, either too restrictive for contribution, or only set up for rich families or rich grandaddies.