8) Make your signup simple, only ask for email address & password. Why would you need a username & email address? Both are unique identifiers for a login.
9) Change your website design. a) Go to https://wrapbootstrap.com/ and look for a product theme perhaps like - http://wrapbootstrap.com/preview/WB02N6L1H
b) Take out the slider and instead either alternate features like - http://www.lostmy.name/ or create separate pages for the content. Separate pages can help out better for SEO.
c) The copy for why I should use your software answers what it is? You haven't attacked any pain points or said how much easier you would make it. You have only mentioned that it would be easier and scale but this isn't a proper answer. The best way to do this is to create a narrative or story around the product.
d) Bear in mind that h1...h6 tags are used for SEO which you don't seem to have. Check out - http://www.hobo-web.co.uk/headers/ And only use one h1 tag per page as per Google's recommendations.
e) managers@flowstacks.com seems like it might come across as pretentious if you're marketing to developers and startups although it might work well for enterprise customers. Perhaps you should go for hello@flowstacks.com for general queries and you already have support@flowstocks.com for support.
f) Flesh out your about page a bit more, I want to know who you are and why you are doing this, history and motivations. You could add testimonials to either this page or the homepage. Testimonials at this early point could come from your beta users.
g) Your navigation at the top is broken on your blog page. A home button is added and the sign in / sign up buttons disappear.
h) Minor but the community button on the documentation page goes back to the homepage. Broken?