agree that it's less abuseable and more appropriate (idk if there's a better word) since you're already not standing alone in those areas.
crossing a line in the sand, idk. Personally it doesn't make sense to say you can benefit from a different horn but they still can't venge you. Similar to the "boss pets" getting 200m skilling bonus, I don't like it, I don't think it makes sense but if you're going to do it to one of them apply it to the rest of them.
If the goal is so irons aren't disadvantaged in a team, I don't think this does enough to bring them up to a main raid team party. on the other hand Is something better than nothing? maybe.