Honestly, I didn't think it was too bad. We were through security and waiting to enter about 5 minutes before the welcome show. I did want the "I was here" pin so I got in the line for the Emporium. I thought it was fairly organized and was through the line paying for my pin about 58 minutes after rope drop. Now the line did get ridiculous, wrapping around and all the way at least to Adventureland, so I'm sure there were some that missed out. If the merch is important to you then being ready to enter before rope drop and heading straight to the Emporium to line up needs to be priority number one. Crowds were not too much worse than a normal Saturday I don't think. Though we did hop to Epcot for a few hours mid-day before returning that evening, but that was always our plan for the day. I would expect the 50th to be a much bigger deal. To me, that's an actual major milestone, not just a 5 year increment of an anniversary.
