Poland lets you be super duper greedy with your social policies. Fitting in things like 2 points Piety (for the faster and better Temples/Shrines) , 2 points Patronage (for the permafriend bonus w/ pledge to protect spam), and even 3 point commerce for the much cheaper rush buys are all options while still going full on Rationalism and getting your endgame Ideology "finisher" up and running.
The stables were less than impressive, but it's not a dead building by any means. I had some of the UU but didn't need to use thing -this wasn't a warmonger game for me this time.
That UA is just really flexible-I had another game where I used it as a crutch while I went all-in to kill Genghis and cripple Shaka-yes, my two neighbors-before they got their UUs out. Flexibility isn't quite as strong as raw power focused into a linear strategy (see Babylon, Korea, Zulu, etc.) but it's better than the 12 gold and four culture you get from that POS Morocco UA that took three days to get a Deity win with this week.