If you open this up to everyone, you may as well remove Gunboats altogether. People will simply counter the new "Research frigate" with one of their own. Soon, everyone will be using them. Pirates, escorts, probably even factions with their own gunboat are going to use these simply because they are more powerful.
I see the appeal as a research vessel, but there already is one. If you are going to tone this one down you are just making another Audouri.
Alternatively, if you wish to avoid all of that, you could simply remove the CD mount. There needs to be some trade-off for the extra cargo, weapons and/or power - CD would be a good start.
