You have to separate what you did as a swimmer and what most do as masters tri swimmers. Sure if you are doing 60k a week, you can do a lot of drill type stuff. But what if you only get to do 14k a week? What are you going to chop out? I think what these guys are saying is that if you have limited time and mileage to do, then you have to do it mostly all hard. And if you have form issues, put on the toys that mostly correct those flaws, and keep hammering. It has always seemed funny to me that many good swimmers are so anti toys. I know where it comes from though, toys make most people faster, and there is a built in hatred for those folks that use the toys. Swimmers had the same feelings when wetsuits were allowed too. Cyclists had the same feeling when the 1st aero bars were shoved down their throats. People hate change, especially when it makes others faster than you. Sutton may not be very literate or have a good bedside manor, but he is right for the most part. If you are a tri swimmer that is in the hour+/- range and have only a few hours a week to swim, put on the gear and hammer out big sets. that will be your biggest bang for the buck for tri/wetsuit swimming. If you form is really good, then just do the hammer sets without the toys, same result.
I was/am one of those that pull a lot in workout, along with Dave Scott and dozens of other top swimmer triathletes i have swam with over the years. Not only does it not hamper me, it allowed me to swim with the lead group every year in hawaii, a group that would swim circles around me in just plain pool swimming. Even now in my advanced age, doing big pull sets helps me hang with many lead groups still. Dave was also never a super fast pool swimmer, but never got dropped in tri swims with guys faster than he was. I believe it is a power issue for some, and others it just plain corrects their flaws and enables them to workout like they are going to swim in the race.