Yes, however that doesn't change the fact that in American politics you still need to be able to work congress (especially in this period of time) to get legislation through and Reuther doesn't have anywhere near the influence that LBJ has. Yes his position as one of the leading Trade Unionists...
Considering he lacked LBJ connections and experience with Congress, I'm going to guess he will likely end up achieving a lot less than LBJ.
Theres also the fact that if Kennedy picks Reuther as VP, Nixon stands a better chance of winning in 1960.