Gonna disagree on this one. Barriers are equally important in lower ranks because positioning and awareness are far worse, as is good healing priority, so people take way more spammage. They’re not as tightly constrained by meta, so you do see more diversity in tanks, but often if you have a barrier-deficient pair going up against a pair with at least one barrier, the barrier pair will win.
WB comps are one of the few exceptions, but it really requires that both your WB and other tank be good. As in, they’re probably relatively better than the rank that you’re in, i.e. smurfing or just climbing in general. I’ve seen crazy off-tank pairings win games–heck, I saw a DVa-Hog combo win a game handily before–but exceptions don’t make the rule.