The first and more broader improvements that will apply to all Android users have to do with personalization and smarter search. On the first count, the Play Store will actually make sense of your currently installed apps and refine its results based on this information, while on the latter — search results will now be split into categories. So if you search for 'shopping', you'll get a choice between apps that let you buy stuff, and apps that let you get your hands on them for less — like coupons aggregating apps.
Another significant change to the Play Store is aimed at parents. The Play Store will now be much easier for them to navigate and sift through for appropriate content, as apps will be tagged with a special, green 'Family' star to indicate this. Apps for kids will also be available in a 'Family' tab within the Play Store, where parents will be able to further specify their searches with age groups. Moreover, Google is making a ton of different characters that kids love — like the snowman in Frozen, or Dora the Explorer — actual search criteria. So if your kid is crazy about this one particular character, you'll be able to easily get content that features him or her.
In all, while such improvements aren't as sexy as a UI design overhauls or new features, they're nevertheless always welcome. Whether you consider this trivial or not, the Play Store is an integral to the Android experience, and we for one have been wishing for better search algorithms for a while now.