Suggestions for weak civs

All civs aren't created equal...

In KotD2 we saw a wide pool of civs due to the no repicking rule, but there were seven civs that weren't picked even once (Goths, Italians, Koreans, Persians, Portuguese, Teutons and Vietnamese [ty Tarsiz for the statistics]), and some that were picked once or twice. While 1vs1 Arabia is just one game mode and some of these teams excel in other areas, like Italians on water, Teutons on Arena and Koreans on Tower Defence, it's a fact that some civs could use some love, just like the Franks did a while ago.

In this post I'd like to explore how the weaker civs could be improved. Numbers tweaking could work, but adding techs or even new bonuses would be more fun. As a basis for discussion, I'll start with some ideas in the comments: