No, soreness is never a gauge of progress, either in improving muscle mass or strength. The same as a good pump is never an indicator of doing anything but increasing the blocked and pooling of blood in any one muscle area.
Your body is never guessing but adapting, which requires steady stress (more weight and/or more reps per workout). Always changing (to keep a workout "fresh") the exercises/sets/reps before really working them to their full potential, after so many weeks/months, can be cheating yourself out of improvement.
You want to push yourself, but not to the point of making recovery from any workout that much harder. The CNS is the key for progress on a workout to workout bases. Making any workout short and to the point, plus avoiding going to failure, is a most important element is successful training.
Working out and making steady progress is pretty simple stuff...really. Good Luck.