I think my biggest pet hate with AI is the self service, especially with kids serving themselves, I've lost count of the times I've seen a child pick up a sausage, hold it then put it back. It's disgusting!
I agree, having done it lots, its so easy with young children but once out of that age group, I find its a much nicer meal eating out. For us, as the kids have got older, the many negatives of AI are starting to outweigh the positives (or possibly that those annoying things such as kids fingering the food and people piling their plates to oblivion just because its free are more obvious now the kids are older!).
It is good value going AI but after many years of it, I'd say we've definitely sacrificed certain aspects of the holiday. With older kids, half board is easier as they tend not to waste as much food, they know what they like, kids themselves start getting bored round the pool etc all day.
Mine loved the kids discos in the hotel til they got to 6 but now couldn't care less which I'm pleased about really. Going half board, evenings are often based around meal and a bottle of wine, whereas in AI complexes (not all) its easy to sit there drinking for hours watching hotel entertainment whilst kids entertain themselves. Not saying all AI hotels are like this but many of those we've been to certainly are.