The one big thing that I absolutely have to change is the mechanism for using full autofire. One option for autofire would be to send several bullets downrange to increase the chance of hitting a single target. Another option is to attempt to hit the target with multiple bullets. A third option allows for area fire to hit multiple targets in a 10' diameter. As a fourth option, spraying a full magazine in a cone would still be possible.
These are just the rules from T20 Traveller, and its supplement TA-1 Personnel Weapons of Carted Space.
I do want more weapons to be available at level 1. There isn't much selection at all.
But more significantly, I think I would change the stat boost rule to say that when you apply a stat boost, you get +2 to a stat if the stat is 17 or less rather than 16 or less. This gives you something to look forward to with that stat with an odd number, which you are forced to have.