I don't think things are that black and white. It isn't an either/or situation.
I don't mind changes and deviations from the source as long as who these characters are at the core stays intact. In fact, I would argue that's been a huge part of Marvel's MO since '08. Taking the best traits a character has to offer while reinventing them for the big screen. This is especially true with Thor and Iron Man. Hemsworth and Downey, as well as their writers, gave them an excellent characterization that's different but intact/in-tone with the comics.
I start to draw the line where characters get INO'ed (in name only) or have their spirit/essence snatched from them, with the spirit and essence varying from character to character. By the latter part, it could be a case of removing a specific message/moral that comes with the character, or a specific character struggle of importance, etc.
Those two factors are why I was never on board with this in the first place. I don't think Hank and Jan ever deserved any of this. More specifically with Hank. I always saw him as the most important Avenger after the Big Three (Tony, Cap, Thor). Founding member, been with the team since the beginning, is one of Marvel's brightest minds and has worked with the likes of Tony/Reed, has been one of the smartest men on the team and has done a lot in terms of gadgets/science, is heavily tied to Ultron, has bipolar disorder which plays into his dynamic with the team and how he views himself, always tries to atone for his mistakes by contributing to the team, Avengers Academy, etc.
To offer an "in a nutshell" of it, he is to the Avengers what Martian Manhunter is to the JL. There is no team without Hank and there is no Hank without the team. I'd argue BW and Hawkeye fall in that category too.
Due to that, I was never on board with any of this. Isolating him from the MCU, aging him into an old inventor, stripping him of all connections to Ultron and the team, turning him into a supporting character (or villain) in his own film, essentially making him INO...I don't think Hank deserved this. Especially with the slow character assassination he's been going through since that out-of-context-taken slap thirty years ago. If anything, the "boom" of the MCU would have been the perfect time to undo that.
However, that doesn't mean I wouldn't accept any deviations from the source. In some cases I do, in some cases I don't. It depends on whether or not I like the idea. In Hank's case, I didn't. But I accepted other deviations from Marvel in the past.
I actually wouldn't consider myself part of any group. I think faithfulness to who these characters are is just as important as telling a great interesting story/film. Both are necessary components to success, and if we look at most of the CBM's fans generally praise, they were mostly films that managed to achieve both. TDK and Avengers are the biggest examples, with both being huge cultural phenomenons.