So many people are acting as if Amanda is the biggest threat to the show, and perhaps she is, but not in the way they think.
For starters, Amanda said she was told Mary had a secret but not what it was. When they told her about HLV, she was already in, committed. She even said she told them, “They’re going to hate me,” when she saw the script. But the Mary of TEH and TSoT was brilliant and no one (in fandom, at least) was complaining about the wedding at that point because it allowed for the stag do and the best man’s speech and everyone thought it was brilliant (even if they were all sad for poor Sherlock). But HLV is not end game.
Meanwhile, everyone involved continues to rave about how much they enjoy working on such a brilliant show and managing to fit it in their busy schedules. But it takes them all. “Sherlock” or not, what would Sherlock be without John? HLV gave us a bit of a hint that we wouldn’t enjoy that show nearly as much. But — and here’s the part no one considers as far as Amanda being a threat — how much hate does Amanda have to get over a TV show before Martin earns his grumpy reputation and (justifiably) walks away? It’s clear that he absolutely adores Amanda and people not just hating her but sending her hate really makes him angry. I think, more than people demanding that he and Benedict read porn at public events, that is the threat.
If people don’t calm down and separate the character from the actress, Martin can walk away.
Amanda can walk away.
And I don’t know that Benedict (or any of them) would stick around if Martin and Amanda are feeling so offended.
That set is a family. They prove it in almost every casting decision they make. Hurt any part of the family and none of them will stand for it. (Even if they all mostly have developed a thick skin about the criticism — particularly in Moffat’s case — there’s a different between criticism and sheer hate. If Amanda actually feels threatened, none of them will put up with it.)