I certainly feel like the smaller transports should be able to fight VHFs effectively with practice. The big cashcows that exceed battletransport size should probably die when shot, and die rapidly, without escorts. A lower max theoretical cargo in a transport should buy you some survivability.
This is from the perspective of someone who benefits from transports being easy to wipe, since it encourages people to pay the pirate rather than flee.
The flip side is that suitability should be ability to survive engagement whilst running away for long enough to get to the nearest NPC station from wherever you're being pirated/accosted by police/Navy. Transports should rarely be choicey PVP tools, except maybe armoured transports.
Low DPS, but tanky enough for a a VHF to need over a minute to kill by itself, up to five minutes or more depending on competence. Certainly should be able to kill its accostors, but not in burst damage. After all, there are plenty of server rule violating transports who try to nuke the pirate without RP mid-demand-line.
THE SYNDIC LEAGUES
(A co-operative of Rheinland's outlawed trade unions, determined to take the underworld for themselves.)