Currently, you can only get viewers of your blog to subscribe if they make it all the way to the end of the blog and past the 'share' buttons. This reduces the ability for the writer to get subscribers. For example, I have had over 100 shares through LinkedIn of my first 5 blog posts in 3 weeks, yet only 2 people made it as subscribers. This sounds like viewers are not easily seeing the subscribe button.
My suggestions are as follows:
1 - Add a subscribe button to the home page of the blog section, so everyone can benefit from it.
2 - When creating a new blog, there is the ability to add content, here you should be able to add 'subscribe button' just like you can add a Separator - so that the writer can add a subscribe button at their choice.
3 - The subscribe button should be published as HTML code so that the website owner can add the subscribe button to anywhere on their Strikingly website.
4 - Create a Hello Bar feature for the blog, so that viewers can subscribe automatically.
Overall, the blog feature is very well executed, I would not want to move aware, just because other blog/newsletter services make it easier to get sign ups.
Remember, most of the sites that are built on Strikingly are low traffic sites, so having the ability to get viewers back is critical to the success of your clients and the Strikingly business model to keep customers and returning individuals for a blog is a great traffic source.
Look forward to hearing what you think! :)