These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Magnificent Bastard: Redbeard. Given that he's in charge of Avadon (and thus the Pact), its practically a job description.
Heart Miranda. After her attempt to have Redbeard assassinated fails, she spends the entire game sending the player on missions specifically designed to make them question the validity of the Pact, in the hopes that she'll be able to turn the player against Redbeard and have them succeed where she failed. Whether or not this plot works is up to you.
That One Boss: Redbeard, the Final Boss before the rebel ending, is widely hated by players for the sheer annoyance of dealing with him. What makes the fight annoying to many isn't so much that its hard, but that its tedious. Before you can even face Redbeard himself, you have to run around and destroy a bunch of golems that function as his Soul Jars, all of which have an obscene amount of health and are spread throughout the large arena. Once you've finally destroyed all the golems, you find that Redbeard's only real strength is his obscene healthpool.
They Changed It, Now It Sucks / It's Easy, so It Sucks: Given that it's a throwback in so many ways, a lot of people were disappointed at how much easier this game is than the standard '90s Western RPG. (For what it's worth, Torment difficulty is still painfully hard.)