@Silver your “peanut butter” proposal is slightly different from the TiddlyWiki “Freelinks” plug-in in that it gives you a choice whether you want to create that link or not. Freelinks automatically marks a word as a clickable link in the Preview/Read mode, though in the Edit mode you can add the [[ ]] if you want to have it visible in that mode.
The limiting aspect of both proposals is that for multiword titles the plug-in relies on you using the exact correct combination of those words.
I prefer your proposal for a plug-in.