I am looking for a toy that is like Little People in that you can keep expanding your collection. I like that little people has so many themes (zoo, firetruck, airport, etc). I don't like that they limit the use by adding the sounds.I don't like that they are made only half thought out. Ie. they can be frustrating because the wagon won't stay hitched to the donkey. The airplane doesn't fit the airport.
I'm going to speak in defense of LIttle People a tad - no, the airplane doesn't fit the airport, but all the figures fit all the places where figures would go. So if Rapunzel wants to drive the Batmobile, or the monkey wants a turn in Wonder Woman's invisible jet, it works fine. I am mostly contrasting with Imaginext - We have a ton of Imaginext figures, but have been frustrated by the fact that not all the figures fit all the vehicles (some of them have feet or headgear or capes that keep them out of certain positions), and, for a long time, there was only one girl in the entire Imaginext universe (Catwoman). There's now Catwoman and Wonder Woman, but let's just say we think they could do better. We have not been troubled by issues with sounds - the barn moos no matter what you put in it, and the first thing we did to the Batmobile was yank the batteries because it was creeping DD out. (There's something of a superhero theme in my house, but we also have the zoo playset.)
I have not yet found a hand-sized toy wagon that will stay hitched to a toy donkey. The people who make toys are terrible at hitches.
I have a soft spot for the little people sets, though I agree some of the scales can be a bit odd. Neither of mine really took to them though.
The playmobil 1 2 3 sets are nice quality, but the people are slightly bigger than the other playmobil sets so they don;t work together. We didn;t find many options for the 1 2 3, though that was a few years ago.
One of our most played with was the duplo, we had a few sets with people and animals, The buildings do need a bit of, well building, but most of the vehicles are one piece. It's grown well with them too, my nearly 7 year old still enjoys building with it