Hello hello all!
I've been GMing S&S for a couple months, and aside from some slow moments in the first book, my players have been having a blast. They made friends with nearly every possible NPC, (and one or two impossible ones thanks to lucky rolls) and they hated Plugg and Scourge the perfect amount.
However, when it came to the mutiny, they seemed mostly confused and resigned. As the AP dictates, rumors of insubordination start to plague the ship once Plugg is in charge, and my PCs replied to all of them with "Who the hell keeps saying we're gonna mutiny?!" because at the time, they had not made any actual plans.
Once they were on the island, I decided to have Plugg pull one aside and tell them they should "Come straight down the beach. Don't go through the jungle, don't row a jolly boat over. Just sit tight on the beach and we'll come get you." My main reason for doing so was to showcase Plugg's advanced paranoia, and my secondary reason was to give the party the choice of what kind of fight they got. They could go down the beach or sail over to the ship and deal with ranged attacks before boarding (as is written), or they could try to head through the jungle in which case an ambush (albeit a slightly less dangerous one) awaited them.
I was perfectly satisfied with this plan, until my players started talking about the rumors of mutiny later on. None of my players were excited for a mutiny, and none of them really had a score to settle. Oh sure, they all hated Plugg and Scourge, but not enough to pick a fight just yet (plus they were very worried that they couldn't handle either of them). So it seemed like the mutiny as planned wouldn't be very thrilling or satisfying, they were sort of resigned to "Well I guess we'll just figure it out when it happens". On top of all this, the PCs had befriended so many other pirates that I wasn't sure how difficult the fight would actually be.
So! I scrapped the whole thing and came up with a new plan. A much, much better plan.
While the PCs were on the island, I read the party a cutscene of sorts. Plugg calls the crew together and announces that he's tired of these rumors. He tells the crew that when the PCs head back, they're going to have a trap ready. At this, a few of the party's favorite NPCs speak up, saying, "Like hell we will!". This showed the players that they did indeed have friends, and they enjoyed hearing some insults finally lobbed at Plugg. I gave them the sense that Plugg expected as much. He's been hearing about insubordination for weeks, and he knew they had some allies.
However, when Plugg challenges any disobedient crew members, not only do the favorite NPCs draw weapons, half the entire ship does as well. Plugg, very much not expecting this, screams "MUTINY!" and commands all officers and still-loyal crew to fight. This showed the players just how successful their diplomatic efforts had been.
For the fight itself, I gave each player the stat block of their favorite NPC (all level two, with Ambrose at level 3). Before we started, I told the party that as veterans aboard the ship, their characters know for a FACT that they cannot take on Plugg. They fought against some old enemy NPCs and Scourge, while each round Plugg got closer to them. In the end they killed a decent number of officers before parleying with Plugg, and he offered them a deal. One person from the main party vs. him. Winner takes the ship.
I don't know if this re-write is usable for other groups, but I can safely say my group nearly flipped the table with excitement.