How to manage intangible products

Well it depends what is your products. Is it an asset or a goods/services that your are selling?

I do not think it is good to use assets for intangible. For now you can use a service and defer the cost over the validity of the license for example.
But for the rare intangible assets that must be deprecated over a “flexible” period (with the account_asset module). I think it will be good to have a product type like assets but which is not allowed to use on stock move.