If we're looking at ways to alter mechanics, you can increase strength, money, or speed. I'd suggest awarding an escort fee to escorts, without deducting from the trader's profits.
This could work on multiple tranches, by stacking awards.
An award for being /escorted, an award for being /escorted as a member of the npc faction IFF and ID, an award for being /escorted as a member of the Tagged faction, an award for being in an appropriate freighter.
I'd suggest only allowing fighters and freighters to be escorted, and making the escort award proportional to between 2 and 10 percent of the escorted ship's profits.
So, a merc fighter signs on to a convoy, makes a 2% stipend. (2%)
A Bowex fighter sings onto the convoy, makes the 2% escort and a 2% IFF reward. (4%)
A Bowex frieghter signs onto the convoy, makes the 3-4% escort and a 2% IFF reward. (5-6%)
A Tagged Bowex fighter signs onto the convoy, makes the 2% escort, the 2% IFF, and a 2% Tag reward. (6%)
A Tagged Bowex freighter sings onto the convoy, makes the 3-4% escort, the 2% IFF, and a 2% Tag reward. (7-8%)
This system has the additional bonus of encouraging people to fly freighters.
Now, something would need to be done to make sure the escorts stayed somewhere near the transports, but increases incentives to fly in convoys...for smaller ships, anyhow.
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Oh! I forgot. I'm obliged to say that giving transport vessels more and stronger weaponry would definitely not hurt, and that the actual layout of the economy is less than mentally stimulating, engaging, or fun. Inter system and inter region routes which net reasonable profits so that a tradeship can actually stay inside an RP without sacrificing its primary activity would be nice.