1: Old achievements, Warcraft Logs, WoW Armory. The systems are there but aren't used because they aren't convenient in a queue, which again, being able to differentiate or be guaranteed an invite was never my argument.
2: Is the selfish attitude I was talking about. "I'm better so none of my dungeons should ever fail and I shouldn't have to teach or help anyone ever." Not every dungeon is a do or die situation where you specifically need to time it. If you are using pugging as an effort to push your own keys to high levels, you really should get a solid group instead.
3/4: Where have I said that I want to change it? I'm merely calling it out for what it is, because if people want to change it, they have to be the change.
1: They aren't required, but if people spend their time complaining about how bad pugs are instead of spending that same amount of time helping them... They are only making things worse for everyone. Some people pick up litter on the street when they see it, and others just walk past. If nobody picks up the litter, then we are going to be in a trash heap.1. Players don't have an obligation to be teachers/mentors. Sure it could be nice, but that's not their role. That's why we have a new guide system in WoW. You want teachers/mentors then start your search there.
3. Old achievements also don't matter in current because it's no longer current (and outdated). If you compare any raid encounter from Classic at the highest difficulty of Classic and compare it to say the mechanics of Mythic Denathrius, you can easily see how much more difficult current content is. In fact, there's an article write up somewhere a healer (I think) posted about how much WoW has evolved in fight mechanics to the point where DBM/BigWigs is absolutely necessary because of so many mechanics to keep track of.
4. It's not that you need to learn the content before you go do the content but rather learn the content on someone else's time instead of mine.
5. If you want supportive of players then your best avenue to find it is within a guild or a community of like-minded players. You're not likely going to find that in a PuG.
3: It depends on the achievement honestly. M'uru from Sunwell, Yogg+0 in Ulduar, H-Putricide and H-LK from ICC or even Mythic Cenarius/Xavius were way tougher than really anything I have seen in CN so far, granted I haven't stepped into mythic CN yet. Again though, you are one of those people comparing the extremes of an argument no one ever made. If someone is 197 ilvl with no experience in N-CN, there is no real reason why they shouldn't get an invite unless you are selfishly looking for an anima farm run. It's entirely possible to purposefully bring 1-5 in your raid pug to help get them that experience as well. I'm not saying it's required, but it helps the pug community as a whole get better players, and helps motivate those with a will to get better to do so.
4: refer to answer 1.
5: refer to answer 1.