I'm going to ignore some of the responses around here because a lot of them are just unnecessarily inflammatory (And being XI's internet defense force isn't going to help the game any).

Pretty cool of you to post this, actually, Crevox. I've played the game since it launched stateside and it's interesting to hear the kinds of frustrations I would expect a newer player might run into. It's true that a lot of the things in the game are convoluted, and I think a lot of it has to do with a revolving door of developers that patchworked the game for over a decade, to the point where there is stuff that is there and serves no real function (the Colosseum in Aht Urhgan was never used, for instance).

The thing is, Seekers of Adoulin was designed almost entirely with people like you in mind. To be blunt, a lot of the things you did weren't necessary at all. I don't think it'd be at all necessary for anyone to do the majority of the old content, because a large amount of it was phased out. Right now, to wear the most up-to-date gear (The reforged artifact armor +1), you need:
-Rem's Chapters 6~10, which can be obtained solo or in an exp group using Records of Eminence
-A crafting material, which can be either obtained through hard mode difficult+ SKCNMs or hard mode Ark Angels
-The original AF
Consider what you need to actually do for that:
-Don't need to do a single mission (You need to be rank 6 + cleared zilart to do Ark Angels, but the hard mode BCs do not require any)
-Don't need to gather any old content outside of your AF (Which is something I think you should do anyway since the storyline for your class is sort of a big deal, it's not asking you to go gather 5 golden goblin ribcages for some obscure old lady)
-Don't really need to grind much old content's gear (take a look at the adoulin and records of eminence gear and you'll understand why, it's all designed specifically to be very easy to get as "starter" gear for new players hoping into the group scene)

In other words, they're trying to design a game in a way so that they can both keep their long-time players and newcomers alike happy. The problem is pointing newcomers in the right direction has not been done very well if your confusion is any indication. If you had done the past events you would certainly have an advantage, but it is not necessary to do endgame, just some of it. I do agree that in the future they should try to add non-mission gated and mission gated content at the same time so people like you don't get left out though.

One unfortunate part is that you chose one of the most newcomer-unfriendly jobs in the entirety of the 22 job system. They should have an official for this somewhere because I would definately list SMN at the bottom of the choices a newcomer should pick. While a few years back they made it easier for you to get the prime avatars at level 20 (They used to require long and difficult level 60 quests that were at the time quite difficult and fame-intensive), they left the difficulty in obtaining ones such as Fenrir, Odin, Alexander and Diabolos because they were supposed to be like quest rewards (think of some of the other FF games where you had to go get "secret" summons or somesuch, it's in the similar vein, except EVERY prime avatar used to be that).

As for Mythic weapon, however, never ever think that that is necessary for your job, I am against alleviating the requirements for it just as much as every other hardcore player, and I know you think that's odd, but the entire point of the legendary weapons was that they're supposed to be rare and powerful long-term project weapons that not everyone has. If you want you can make a joke about epeens or something go ahead, but they made sure to balance the newly-added high level weapons so that they would not be an absolute requirement (in some points in the past they were which caused all sorts of problems, this is not nearly the case anymore).

Anyway there's a lot of stuff I might've missed from your post to respond to since there's quite a bit of it. I agree with you on some points and not so much on others, because I don't believe in removing every last gate there is because lifting those wouldn't be necessary to actually play the game.