For those who are doing the seemingly NEVER-ENDING series of quests in the Crucible, Leif Johansen, chief Crucible quest writer told me what it's all for...

He tweeted me this:

https://twitter.com/LeifJohansen/status/644187110098931712

So we HAVE to do these quests to unlock the weekly bounties with Shaxx, which then have a chance of dropping an exotic.

He also told me where the end is, as it seemed to be never ending!

You do the first quests for Shaxx, then for the three factions, then Arcite, then the Gunsmith, then once more back to Shaxx for the final challenge. A challenge which I am just about to see for myself!

Good luck everyone, keep plugging away! It'll be worth it!

EDIT/UPDATE:

The steps after the initial ones with Shaxx are:

Dead Orbit - Win three games of two different game types (they tell you which) in the Crucible.

FWC - Win three games of two different game types (they tell you which) in the Crucible.

New Monarchy - Win three games of two different game types (they tell you which) in the Crucible.

Shaxx - Win 5 games of Elimination.

Arcite - Win 5 matches where your score is over 1200.

Gunsmith - Win 3 matches (of any type) with 6 auto rifle kills.
Win 3 matches (of any type) with 6 pulse rifle kills.
Win 3 matches (of any type) with 6 scout kills.
Win 3 matches (of any type) with 6 hand cannon kills.

Shaxx - Earn 9 points. 3 points for a win, but lose a point if you start a new match.

UPDATE TWO: I've done it! Granted access to the weekly bounties and got the HotHead rocket launcher! THANK THE LORD!

UPDATE THREE: Some of you have asked what he weekly bounties are. I'm just about to hit the hay for the day so I'm not near my PS4 to fully confirm but off the top of my head they were:

Win two games with a score of 1500 or more.

Win a match in three different Crucible types, Skirmish, Elimination and Clash.

Take part in the daily crucible playlist, on three separate days.

Score points in the crucible. 3 for a win but lose a point every time you start a new match (I think you need 6 points total?)

Win 7 crucible matches.

Complete all of Shaxx's weekly bounties.

There might be one I'm forgetting but I'll check in the morning and update this post then.