As someone with 4 kids myself, but who are now all in their 20's, it is definitely the case that having young kids in your group requires a lot more flexibility than having teens/tweens or all adults.
When I got serious about using FP in 2003-2005, and FP window closing times were not enforced, I would easily get 6-7 FPs per day between DL and DCA. But it took lots of FP running around. And I had to get there for RD. WDW was similar as far as getting 6-7 FPs per day. But rope drop was critical. After FP windows were enforced, that effectively limited my FP collecting to more like 4-5 per day. Which is not that different from how many FPs I got last month using FP+. About 4-5 per day. The difference though was last month it was easier to get the FPs for windows that worked for me when we wanted to take an afternoon break or leave the park early that day.
For me and my current situation as far as kids (or lack thereof), plus being older now, I have come to appreciate the tradeoff offered by FP+.
Yes, I have to book the FPs 30-60 days in advance. I have found that is just not as big a deal as I expected it would be. I know what FPs I want for the most part and now I can get them without having to run around. I also do not stress about rope drop like I used to because I know I have the critical FPs I want. In advance.
Yes, tiering can be frustrating. But that is more because WDW parks need more headliners like the DLR parks have. And WDW is working on that.
You are absolutely right about #6. But I have found it is not as bad as it sounds. Usually. Sometimes it is as bad as it sounds though.
Your #7 is true as well. But after WDW started enforcing FP windows that really cut back on the ability to get FPs for headliners. Yes, you could get more FPs for headliners under the old system. But only if you arrived for rope drop. If not, you can get an equal or greater number of FPs for headliners using FP+.
A good example of how this works for me is another WDW trip I am taking next month with DS26. I had planned a down day for us to relax by the pool. But with Pandora opening, I was able to book Pandora FPs for the evening plus the new Rivers of Light show. So we can sleep in, relax all day by the pool that day, and head to AK at 5PM for dinner, then start using our FPs at 6PM. That is really cool.
I cannot really say I have a stronger preference now for FP+ or FP legacy at WDW. They both have good and bad things about them. I think now I do feel less stressed using FP+. But I know I will probably get 1-2 less FPs per day now and not as many for headliners as I used to. But did I say I am less stressed about the whole FP thing using FP+?
Finally, I have always stayed at hotels that let me get the FPs at the 60 day mark. If I had to wait until the 30 day mark to get FPs like many others, I think that would make me feel more stressed not less. So my growing appreciation for FP+ is tied to my Disney hotel preference.