Hmm... it depends. I've only ever gotten a reaction with my grammar and words, not my plot. I do adjust my grammar and punctuations, but that's it. As for the plot, nope. My novel is quite new and "small" at the moment, and right now there are only two chapters, so I've never really gotten any comments about my plot yet, since the story hasn't even reached the climax; it's not even near there.
However, if I were to get comments about it, I don't think I'd adjust or change the ending/climax. You see, I'm still writing my novel, my story isn't wholly written yet, but my whole plot is already solid and planned. As for my characters... it also depends. After all, your readers can only assume or think of what would happen next, they don't really know what will happen; if a character would have development, if there would be a plot twist, or if there is someone who'd die. They are only able to go with the flow by reading the most recent chapter, soooo...