I personally consider industry the go-to unless I have either multiple monopolies or a copper/tea monopoly at which point Rationalism is a go-to.I wasn't saying that Industry is weak, I think its right where it needs to be.
But comparing rationalism to imperialism, rationalism is currently an instant pick if have certain monopolies (and the tree is plenty strong even if this policy does nothing for you). Imperialism is full of situational benefits as well, military tradition in particular seems pretty useless to me. Maybe I'm underestimating how strong the farm boost is (but i consider it pretty damn good)
Is that imbalance? Probably not. Is that just personal preference? Maybe?
As far as Imperialism goes, I'm not claiming that the tree can keep up with the other two, in fact I'm not claiming to know anything about it other than that +1F/P on farms is fairly insane and free range-promotion as well as better sea-tiles are really good as well.