Ugh you need more universities then that. The extra unit or two want help you if you're already behind on defense. And if you aren't behind, then the extra unit or 2 wont matter. Compared to getting to that next tech faster, and producing better units, its not as useful.
universities are expensive
i give cities a library if they're producing 10 or more beakers (regardless of scientific or not)
universities, 20+ beakers (if not scientific)
this is just a rule of thumb i use, it works quite well and keeps maintenance costs down
scientific, yes, i'll build them more often
but if i'm not scientific, then it's a lot of shields and a fair bit of maintenance
modern age techs, i usually research in 6-7 turns, 5 turns if i can push the slider all the way
i don't particularly care about modern age techs in 4 turns, because if the game has lasted that long, i've likely already won
i don't build defensive units, unless they're infantry, or riflemen if i share borders with a civ who has cavalry or knights
that extra knight or cavalry can mean the difference between a city being taken or not
an extra university won't win wars, and won't add much on
if you have 9 universities, then the 10th won't make much difference
if you have 2, then yes, the 3rd could make a difference
regardless, i prefer to get banks down, since with a pre-build to smiths, i'll be paying nothing for them
marketplaces are in my cities regardless, unless a city is producing 1 shield