It's sadly just a dumbing down which we see in all media nowadays, Netent are under some delusion that we will like these childlike, colourful, fast moving (and losing) slots or perhaps they are just aiming to capture the 'casual' market demographic.
I don't think they would care if every new release of theirs was just a re-skin of Starburst from now til eternity as long as it suits their business model and winning template. It is a sad state of the times, something like DOA would never be released today.
Personally I don't care if they made a non- themed slot with with brown blobs as symbols on a slightly less brown backround, with no music or zany wilds as long as there is a decent paytable and/ or bonus round.
Sadly I think Netent are to busy hi-fiveing each other on their amazing designs and profit margins nowadays, it is a shame they've turned to the dark side with their constant pursuit of proving how clever they are and all the while believing that veteran slotters are too stupid to notice, unfortunately