As stated in the SO answer, the real issue is that without enabling the Sitecore.Speak.MVC.config, there's no route pattern matching just {controller}/{action}.
The answer that will solve your problem is that you need to enable a config on the Content Delivery Servers that enable this route.
There are a couple ways you can do this:
Option 1: Enable Sitecore.Speak.MVC.config
Let's take look at what this config is doing:
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
<sitecore>
<pipelines>
<initialize>
<processor type="Sitecore.Mvc.Pipelines.Initialize.InitializeCommandRoute, Sitecore.Speak.Client" patch:before="processor[@type='Sitecore.Mvc.Pipelines.Loader.InitializeRoutes, Sitecore.Mvc']"/>
</initialize>
<mvc.renderPlaceholder>
<processor type="Sitecore.Mvc.Pipelines.Response.RenderPlaceholder.RenderAddedContent, Sitecore.Speak.Client"/>
</mvc.renderPlaceholder>
</pipelines>
<mvc>
<precompilation>
<assemblies>
<assemblyIdentity name="Sitecore.Speak.Web" />
</assemblies>
</precompilation>
</mvc>
</sitecore>
</configuration>
This config is doing three things:
- Initializing the Command Route (which is really the piece you need)
- Adding a
<renderPlaceholder>processor that renders added content. - Adds the Sitecore.Speak.Web assembly to the list of precompiled assemblies.
So, in a nutshell, there isn't much here that will harm a CD if this config is enabled, but the last two points aren't needed by the Content Delivery server.
Option 2: Enable Command Route Manually
You can create a patch config that is CD only that patches in the **InitializeCommandRouteInitializeCommandRoute processor above to the process above to the<initialize>` pipeline. If this patch config exists on the CM, where this processor is already defined, it won't conflict.
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
<sitecore>
<pipelines>
<initialize>
<processor type="Sitecore.Mvc.Pipelines.Initialize.InitializeCommandRoute, Sitecore.Speak.Client" patch:before="processor[@type='Sitecore.Mvc.Pipelines.Loader.InitializeRoutes, Sitecore.Mvc']"/>
</initialize>
</pipelines>
</sitecore>
</configuration>