I think it SEEMS much faster, because there are fewer episodes. Tommy found out about Oliver 2/3 the way through the first season, Laurel by the end of season 2, Thea by the middle of season 3, etc. But those were long seasons. In comparison, I think the reveals of Clark's identity are happening slower than they did on Arrow. And if all of Smallville finds out Clark is Superman- eh, that's what? 100 people and some cows? It's not like the DOD will force him to reveal his identity in order to get them to protect the city, or like he'll do something incredibly stupid like sit down for an interview with Cat Grant....