I am fine with the debian minimal approach (so far). Currently, I am building a minimal script which should be very modular, easy to extend and provides some help within the install routine.
The downside, the lines of code are growing and this makes the quick code audit more difficult. Please give me a few more weeks. I would really appreciate some feedback.
If you are interested in its curent status I can share some screenshot (direct message me).
Back to the topic, if you go for one (main) application per AppVM, minimal template is a perfect approach imo. It is getting more difficult if you have new / not so common application. For this I have started a Wiki to better share the right set of packages. Unfortunately, the deb-mini community was not active here.