I usually keep my salsa's a little more simple. I usually just use a few fresh ingredients, mix and serve. But just because yours is a bit more complicated doesn't mean it should be short on flavor. I usually don't use garlic in my salsa, unless it's a roasted salsa (either rojo or verde). I usually don't use vinegar in my salsa's either...I like to keep it fresh. But that doesn't mean you can't put together a fantastic salsa with it, because you certainly can!
I'm guessing your salsa need more salt. Personally, I wouldn't use a flavor packet...but salt can go a long way. If you made a large bowl of salsa it can use a decent amount of salt. If your husband can't have a lot of salt then you need to find some way to bring the flavor forward. I'm just not sure if anything can be as effective as salt in this case. You can also try some lime juice and lime zest (or use a lemon if you don't have a lime).
could you possibly make two bowls? one with low salt and the other with a higher amount?
You probably had weak tasting tomatoes. Salt would help but that's out for your husband. My next suggestion is also a little salty, but something I picked up from Jacques Pepin in his Fast Food My Way books. He uses a little ketchup in salsa now and then. I think a little ketchup will help punch up the tomato flavor. The other tomato options, (paste and such) would taste odd, uncooked, harsh.