2 websites on a single domain.. cant decided how to do them

i have a client.. they have 2 offices in different cities.. but only one domain as per their company name..
their current setup is :
company.com (just a landing page with 2 button pointing to each city)
and then they have
company.com/city1 and company.com/city2
both of them are separate wp installations (not multisite) and have unique content on both but all other structure is same as one another (actually cloned the one site and rewritten the content).

im quite concerned about the way home page is being utilised in terms of impression to clients and for seo purposes..

what do you guys think the structure of the site should be? i mean change the home page to proper website? or create one page landing page? or leave it as it is?
and will it effect the seo efforts with the blank page with 2 buttons on home page?

please advice.