Looking at the Esplanade at opening it looks like a huge crowd, does the Esplanade crowd thin out soon after the turnstiles open?
Also, to date I have no idea what this "rope dropping" thing is and how it is different from the actual opening of the park. I also couldn't seem to find much in the way of a clear concise defition here or anywhere. Would someone mind to explain? Thanks!!
From what I've been hearing lately, yes, the security lines and the Esplanade thin out soon after turnstiles open.
Re: rope drop: For many years DLR has done the thing where they let you through the turnstiles early, and you can shop on Main Street, greet characters, etc for awhile before they actually let you onto any rides. They keep you from getting on the rides by holding the crowd at the entrance to one of the lands, often in several entrances, with a couple of CMs holding a literal rope across the walkway. Then at official park opening, there is the usual announcement about having a magical day, and they "drop" the rope, and people surge for the different lands. In recent years, ropes are held across the entrances to Adventure Land, Frontier Land, in front of the castle, the side entrance to the castle (that goes by Pixie Hollow and Snow White's wishing well) and Tomorrowland.
Once through the turnstiles, many people will head straight for these ropes rather than shop or visit characters, so as to be near the front of their favorite rides ASAP. I've stood at the top of the hub in front of the castle while the CMs, a minute or two before official opening, cautiously start winding up the rope, admonishing, "Don't go yet, we'll say when," and then tell us to go when the announcement comes. Incidentally, some of my favorite interactions with CMs have been while waiting on rope drop, standing there chatting and joking with them as they hold the rope.
Keep in mind that rope dropping is in no way consistent. Sometimes they let you in at official opening time, and you can fast walk all the way to your favorite land. Other days they will open anywhere from 45-15 minutes early and hold you at rope drop. When (if) Magic Mornings/Early Entry comes back, that often means no rope drop. For example, if you had a Magic Morning to DL on a summer Tuesday with full operating hours of 8 am to midnight, that would mean MM would start at 7 a.m. They would let you through the turnstiles at 7 a.m., no rope drop. On the other hand, if it was a Wednesday opening of 9 a.m. with no magic morning, they're fairly likely to open up at 8:30 and hold you at rope drop till 9.