If every team had two "big hitters" then the current "big hitters" would not be as successful simply because they would be beating each other. The three teams you refer two had a competitive advantage over most of the other teams this year, most of the time, so long as all of the big hitters remained fit. However, in the case of one or more being unavailable, as was the case then there was a scarcity of RR availability unlike for "middle order" riders. Thus there is an argument for a balanced approach across the team such as at Leicester, who finished second in the league, runners up in the play offs (to a great BV team) and actually managed aggregate wins in the league v BV, Sheffield and Ipswich.
That all said, If every team did have two big hitters, heats 13 & 15 would be something to relish and would be great entertainment, Entertainment? now there's a concept for the promoters to consider creating more of!