With a blank section so you can specify why you object. A person posting a picture that's 5000 pixels wide isn't trolling or flaming, but it can ruin a thread just as quickly. Sometimes people's comments deserve an objection but don't quite fit the bill of any of the checkbox option. One more option for "other" with a character limited free response section would be helpful to posters and moderators.

Actually, they should just get rid of the reasons for objections like on mobile site. I doubt the mods even care about why an objection is being made.