As someone who has read the entire family play thread and talked an awful lot about toddlers with people OP I think you'll find that a lot of people wanted more of a TS2 toddler experience. You may be able to get hold of a free copy from EA to try that experience :)
You may have missed a lot of toddler interaction in TS3 by the way because EA for whatever horrible reason made a ton of toddler stuff behind a paid content in the TS3 store. For example-when the tots have the play pen they play peek a boo together, same as if you have the baby monitors where they can cuddle outside of the pen, the pen also teaches them to talk and they learn logic (I think) from it, then you have the walker where they learn to walk plus another skill I forget. The changing table allows you to change or bathe the toddlers. I'm sure I'm forgetting other things too.
TS3 was the start of EA skimping on early years play. They bundled up the baby, no more washing in sinks or baths like in TS2. No more getting bottles from the fridge. Etc, etc etc. It robbed us all of valuable game play and despite my love of the early years game play in TS2 I didn't keep babies long in TS3 and I didn't increase the age period for toddlers like I do with TS2. I have a lot of fondness for other aspects but early years play is not a strength in TS3. TS2 is the best example we have seen so far for that.
You've said it yourself. They've gone all out on skimping in early years in TS4. No toddlers and object babies :/ it's such a shame because these should be part of a sim experience! They should be the centre of a new parent's world and we should be experiencing a really great sim cradle to grave experience by this point in the sims series! I hope you get proper toddlers in TS4 eventually but when they do come it will have been a few years where we couldn't enjoy them and that's just sad. I hope they improve babies too. I'm not a fan of regressing to TS1 type aging in the sims!
