I think that StackExchange websites should be more merged. The way I see it is StackExchange is a company that provides Q&A sites, and each site speaks about different topics. I think everyone should have one StackExchange ID with global reputation (not create an account on each website and get some reputation if you are good on other sites). I think the sites should be less separated and be subtopics of the same site rather than have multiple different sites.
Feel free to agree or disagree in the comments.
Note that although there are a few questions similar to this, they haven't been active for three years.