I think it can be beneficial to emphasize training that extra 20 or so degrees of extension on strengthening exercises that are not specific to sprinting technique, for instance I do explosive hip hyper extensions on the Keiser multi hip, however any “technique drill” I would avoid emphasizing anything beyond triple extension as it could negatively effect sprint mechanics by tempting an athlete to try to hang onto the ground longer to get that hyperextension thereby increasing ground contact times. I also agree that we train that movement indirectly through the many other means of training mentioned.