Well it does get tougher, at some point I had to start using those items basically for myself mostly but I noticed it help others too . And others doing that is definitely what helped me beat the tougher monsters. I just started playing too, 3 weeks ago, level 38, so that's just my experience so far, some people don't help you and don't help themselves, they just drag you down, thankfully that's really not many though.
I definitely learned how to not die in these high rank missions, it really something I like to avoid for obvious reasons lol.
Man, I get it now with the helm slasher combo or whatever it's called, I'm doing it actually right most of the time but I'm not hitting anything usually, sometimes team mates... lol. BUT, it's so awesome when it actually works -- these elder dragons are hard to hit, I mean they're so big, you can basically just go for the feet. Anyways just did it on Xeno, point is, it's really pretty hard, I've seen people pull it off consistently, certainly nice.