I think the new layout does have a childish feel to it,like a website designed for a much younger age bracket than those that frequent this site.The colours look faded somehow,less vibrant,particuarly noticeable in the gems and thumbs up/down buttons.
Lastly,perhaps this is just my eyes but the font looks smaller and narrower which not meaning to sound lazy,makes the text overall harder to read.I'm not saying large text needs to be used,if anything that would intensify the childlike nature of the current layout,but back to what is was before,slightly bigger and more defined,which made it easier to read.