Phineas and Ferb was actually NOT written with kids directly in mind, and as a comfortable pop culture medium between the tame-over-time Simpsons and raunchier Family Guy and South Park. A mostly wholesome, wacky and chaotic series where the good guys always win and usually spectacularly. Phineas and Ferb never really learn anything but the other characters do.

I would say Gravity Falls much more so than Phineas and Ferb. The latter doesn't have much of a series-long story arc, whereas the former very much does have one.

Craig of the Creek was also pretty good, though I don't think it has a wider arc (I am not entirely certain though.)