I find that drills are very good for working on technique, but that the intense focus required to change any one element is so great that it's best done in short course ... focus intensely ... rest ... repeat. I think long course creates an opportunity for fatigue to creep in and sloppiness / old habits to emerge before you've encoded the new habit.
I absolutely agree, for almost all technical purposes SCY is better. My attention span is such that it is hard to keep mindful for 50M. One time I really like LCM for technique is if I am really focusing on my rhythm for the 200 BR. LCM gives me about 20 strokes to get in rhythm vs 6-7 in SCY.
besides the points raised by pwb, the other factor is frequency of feedback by the coach. I dislike coaching LC practices because the amount of interaction with the swimmers is so much less. When working on technical adjustments, 25 yd is the best distance to start at. You want coach feedback each length in the beginning and less often as you make the new technique a habit.
Both short course and long course have their own values depending upon both the level and the goals of the swimmer. From a coach's perspective, shorter-distance pools are better for the more frequent and more immediate feedback that is necessary for beginner or intermediate swimmers. Long course pools are ideal for advanced swimmers who need less feedback and more continuous repetition of proper swimming technique to integrate the elements of the drills into the fullstroke. The length of the pool also depends upon the goals of the swimmer. If it is short course season, it is better for the swimmer to work in a short course pool, with more frequent practice of turns. Long course season is best trained for in a long course pool, if at all possible.
Short course is better for drills and to get more technical feedback from a coach and work on improving technique. Long course is better for a swimmer to practice grooving their full stroke.
