There are plenty of alternatives to every library having to have yet another probably broken security layer. Probably better to focus on this layer being separate from everyone having to implement it.
Why are you connecting to a Redis box across the internet? There's a great (and after Heartbleed, prophetic) post on the Varnish web site about why they don't implement SSL, I imagine Redis would be similar:
I love this post. Not every single piece of software needs to include SSL support out of the box. Sometimes, for the exact reasons Varnish explains, it just doesn't make sense.
It's hard to imagine every service in your infrastructure implementing SSL would be more secure than a single VPN tool. You are very optimistic about the difficulties of getting security right.
It's really simple to imagine and I even have implemented it :) "One single VPN" may (and will) fail sometimes, so count your complexity and stability with and without one extra service.
I'm sorry to be skeptical, but when a random person on the internet claims to have implemented SSL more securely than open source tools that are completely built around security, I tend to not believe it.
Implementing SSL is easy. Implementing SSL correctly is very difficult, and you probably won't find out you did it wrong for a long time, if ever.
I'm not implementing SSL, I just use it. With MySQL you can just use it. With Redis you have to use VPN with all costs of VPN. Please calm down and stop forcing your preference of VPN as the only right way.
As a operations person, this is the wrong way to go. The VPN becomes a single point of failure. Attempts at HA fail in my experience.
Also solutions like stunnel create a separate process that has to be managed. If I have one for redis, and then one for something else it is harder to tell them apart, because both will be named stunnel.