This is very relevant. The Total Immersion technique is all about good balance in the water to prevent your legs dropping and creating extra resistance; stuff like stroke drills are almost secondary.
Swimming, as in front crawl tekkers, is a hard thing to master in adulthood; the best swimmers in triathlons are those that used to swim competitively and train 4-5 times a week as teenagers.
The good news for triathlon however, is that the bike and run are proportionally much longer legs, so...