My take on these lines is that the tapers incorporated in the designs are a bit oversold. I really can't think of what can not be accomplished by an L line, a Level Taper along with a balanced leader to match whats on the end of the manufactured lines to produce a nice gentile extension and presentation.

One quality of a fly line I always looked for was that it float. The plastic lines float relative to the amount of air bubbles incorporated in the line, hence fatter line, more bubbles, thinner line less bubbles. As the line tapers there are fewer bubbles to float the line (the tips sink). A level line has no taper and the bubbles go to the tip to insure it's float-ability. A plus. I think what's bad about the WF is that it's more dense at both ends and sinks at both ends, something I wasn't after.

The question of weight distribution in a lines design occurred to me after switching from a DT to a WF when I was experimenting with streamers and skating flies. I made longer casts to the far bank in these experiments and was out past the normal 30 ft. range of the normal designs. The subtle rod tip movements I was able to give to the fly at distance with the DT were not possible with thin running line of the WF. The rod movements simply died in the thin running line. It was a disappointment. I was convinced the DT was the line for me. Really..in the air neither line made any difference to me. It was on the water, where controlling the line made it important.

In my opinion, I think that fly lines are designed basically for the Dry Fly fisherman on moving water that floats a #14 hackled fly on the surface with enough esses or curves in the end of the subtle line to provide a drag free float and the rest of the fly fishing community just has to work around it. So to my way of thinking that's what your paying for and that's the way it is.

PS: After you turn your DT around for the last time, don't throw it away. Chop all the cracked taper off of it and use it with the blunt end that still has the life of the line left in it usually thought of as worthless and I'll bet you really can't tell the difference.
But by all means if you got the cash, buy a new fly-line, no biggy.