I think it depends on how and where you fish, big windy water or smaller quiet streams. About 30 yrs ago I got a 6 wt cause that was the " all around" line weight for the streams I fished. With the advent of new rod and line technologies I got a fairly fast action 5 wt (St. Croix LU) and with that one rod I can throw a regular DT5F (cortland 444), use a Rio Grand WF5F (kinda like a 5 1/2 wt line) for windy or bigger water and also use a 6 wt line for heavier flies and/or shot. This rod ( and others like it) handles all those demands and fishes big weighted streamers down to #22 midges well. Sure, other rods may be better for a given situation but unless you want to hire a caddy to carry around a golf bag full of rods you'll pick one that'll fish multiple lines suitable to your own conditions.