Hi. I think you're right about Croatia being more properly considered part of Central Europe, rather than the Balkans, but do please keep in mind that this site operates based on consensus. So it's up to you and people who agree with you to persuade the others that it's in the interest of travelers to reassign Croatia to the Central European region. Be patient, and remember that region articles are grouped the way they are due to decisions about convenience, not to please or offend anyone's national pride. Changing the consensus can take a while, and sometimes we never get there and things remain the same by default.
All the best,