Any coaster will have a height requirement, so they'll never be suitable for infants, for example. A proper kiddie area might include a coaster, but it should also include attractions that even the smallest kids can experience. Unfortunately, even A$$ doesn't fit that bill. (TSM existed before TSL, which is why I don't include it in my calculus here).
The same is true of Woodpecker and ET in Kidzone at USF, but that land also has play areas and shows, which TSL lacks.
It's not that I hate TSL as a land in general (I think it's fine), but I don't think it's very effective as a kiddie land.