Gryllida, just to be clear, what you're suggesting is that the very first click on the template should open the edit dialogue, with all the text fields?

(Please do not ping me, I have notifications disabled and only follow-up by hand -- please edit your comment and remove my nickname.)

Yes, it has to be a something with all the text fields. Whether it's a dialogue or a sidebar item or some other interface, I do not care (the design is a bit tricky and I can't say what is better).

Okay, I see. Unfortunately, I'm inclined to think that this isn't something we should do. Even to fairly experienced users, it's not always clear just from looking what is and isn't a template. On the English Wikipedia, {{as of}} and {{convert}} are good example. The situation would be even worse for new users: infoboxes and reference lists look a lot like normally editable tables and lists.
This means we would risk aggravating users who clicked on what seemed to be normal text or images and immediately had their focus disrupted by a modal dialog.

It might be possible, as you suggest, to partially mitigate this by using a something other than a dialog, but a framework for making dialogs already exists in our OOjs UI library. Creating some other interface pattern like a sidebar would take significant development time, even if we could figure out how to make it work effectively across all the platforms we support (which include mobile devices).

If you have ideas about how to make the template editing flow more efficient while still allowing users to discover in a non-disruptive manner that a particular block of content is, in fact, a template, I'd love to hear them. At any rate, keep in mind that it is possible to open the template editing dialog from the context popup just by hitting enter. I personally didn't know about that until your suggestion pushed me to try it out, so it's certainly not the most intuitive shortcut, but I think it does help.