I think we will keep:
{module_webapp .... template=""} to supress the template output (or maybe add support for a placeholder value like {module_webapp ... template="[none]"}.
{module_webapp .... collection="myLiquidVar"} to capture the data in the specified collection.
We will go also with {module_webapp ... render="item" template="item.tpl"} and {module_webapp ... render="collection" template="list.tpl} to differentiate if we would render wither a single item of the entire collection.
We think this is better than the comment inside the template and will simplify things a lot.
One note on why we we would need separate parameters for collection being captured and also for template is that sometimes we do need to both render with a custom template and also capture the rendered data so that you can use it in the page itself (I actually demoed this with module_cartsummary where I would render and also capture so that on the same page to render the related products).
Thank you all for the feedback
-Lucian