I proposed that we add HTML comment tags around the smarty tags (the way XOOPS does) last summer, and a few of us did some testing. It turned out that it didn't make editing in WYSIWYG editors any easier. I personally tested with Dreamweaver 4, if memory serves.
Can you confirm if adding the HTML comment tags does make editing easier? Please update SmartyTplEditingDev with your findings. Thanks.