Oh wow - it sounds like you have access to some pretty amazing classes! I mainly learned how to grade multi-sized patterns beyond their range, and the slash and spread. But this shift and pivot sounds like it could be better suited to vintage - possibly no need to trace the pattern piece AND not destroy it! Hmm I need to look that up lol
Its an unfortunate reality of buying patterns at thrift stores, but in my experience most times they are complete. I found the key to finding some great patterns is consistency - its not uncommon for me to visit the same thrift store 3 or more times a week just to check for new patterns, but I only do this while I can - once I'm working again I won't have the time to find those gems. But I've spent a lot of time looking through them that I totally know which McCalls patterns you're talking about! The ones that get me are the "Marlo's Corner" line where the girls have big, big eyes!
I have yet to make my first dress - but I have a personal goal to sew one for an upcoming wedding this summer, so I'm working on finding the perfect fabric, but it'll be with a modern pattern. I've done a few skirts and shirts now, and its a simple design so I'm not too worried.
I love the 40s and 50s artwork and designs, but I think for my style the 60s and some 70s are more wearable. However, I am currently waiting for this 40s pattern to come in the mail
http://vintagepatterns.wikia.com/wiki/DuBarry_5853. I love the tucks at the shoulders and the shaping at the bodice and waist - I will make this one for sure one day! I was lucky enough to find this pattern in my size for 50 cents at a thrift store, and its my ultimate sewing goal/pride and joy pattern.
http://vintagepatterns.wikia.com/wiki/Vogue_2112 I have no idea what event I would wear it to though!
That's an interesting topic actually - what are the patterns everyone is most proud of in their personal collection?