I don't want to come off as mean spirited or someone looking for an argument; however, based upon my 48 years of fly fishing experience and what I know about fly tournament casting, I must respectfully disagree with the assertion that a WF line "makes a bigger plop" on the water than a DT, or that a DT allows a more delicate presentation, that is unless you are using a bass or pike WF line because of the very fast and blunt front tapers of these two specialty lines. The front taper of a WF and a DT are the same length and profile if speaking of standard WF lines. There are some new WF designs that have compound front tapers, some with very long front tapers that end in very small and delicate line ends and some new WF tapers with very long bellies (standard WF lines have a 30' front taper/belly).
The delicacy of presentation has more to do with one's casting skill, leader design, leader length, and whether using a weighted or unweighted fly than the line used, with the exception of the blunt front tapered bass and pike lines.
And if DT lines were best for distance, tournament casters would use them, which they don't. Tournament casters use WF5 floating lines for the trout distace portion of the competition, not DT5 lines simply because the WF allows them to cast further with the 9' 5wt rods required in trout distance.
And the ultimate long-distance cast single-hand line is a ST (shooting taper) with mono behing it as running line. which is what Steve Rajeff used to set his world record single-hand cast of over 240'. If DT's were the distance champs, Rajeff would have used one. He didn't, nor do any of the other tournament casters.
Likewise in overhead 2-hand tournament casting where a 17' rod is used, Steve
Rajeff holds the world record once again with a cast of over 260'. He used a 50' long shooting head and mono running line to achieve this. And the other 2-hand overhead tournament casters use the same thing. Again, if DT lines allowed longer casts, the 2-hand overhead tournament casters would be using them.
The same hold true for spey tournament casting. Modern compound taper long-belly WF Spey lines are used, not DT lines.
I have been fortunate to have lived in several states near some wonderful spring creeks and I have never felt that the WF lines I used did not provide a delicate enough presentation or that they spooked the trout. I have fished some of Pennsylvania's very well-known and hard fished spring creeks: Letort, Penn's Creek, and Yellow Breeches, and some of Montana's spring creeks found on public land: Poindexter Slough outside of Dillon (it gets lots of angling pressure) and another one I will not name it because it is also on public land, is relatively unkown, and I don't want to see it get overrun with fishermen (locals would know it though) that is a tributary to the Madison River and I never spooked fish because of using a WF line.