What do you in practical terms mean when you say “SEO”? What is it you want to change?
For me SEO is good quality content, clean and valid HTML and some minimal set of meta tags. Your theme seems to do a good job in this regard and the content is up to you.
The theme looks perfectly fine to me, not “weird” at all. What is it you do not understand?
And if you do not like it, why not switch to another?