The B-wing has taught us that slow ships with 1 AGI should not be loaded down with upgrades, as they too frequently can be overwhelmed. The Punisher, of course, has a similar defensive profile, numbers-wise, but has a Boost, allowing for a useful positioning game and Autothrusters, both of which should help it live longer.
With that preface, how many points are too many, and subsequently make the ship too big a target? This problem is compounded by the fact that the TIE Bomber is still hanging around, and is the ship of choice for a budget build. The Punisher brings a lot of bells and whistles that are individually a good price, but add to the ship'separately cost on top of the necessary ordnance load. Consequently, you have to find some happy medium between "not sufficiently more capable than the Bomber" and "giving too many easy points to the opponent". Any ideas?