Boeing has to make compromises in order to maintain a common B737 type rating - which even doesn't include the -200 under EASA.
There is plenty (and I really mean plenty) of room for improvement regarding B737 cockpit ergonomics, such as not getting 10 lights for a simple engine failure, etc., but most of them would probably result in a need for a new type rating endorsment under some authorities.
I honestly hope and believe that given the current Boeing's schedule of pushing B737 generations - every 15 years - that MAX's successor would be designed from scratch (or at least from 787's platform).