Karma currency/armour
All the complaints about people needing to ping gear isn’t the fault of arenanet though, it’s the fault of the community with certain elitist players.
If you are looking for players to do dungeons, your best option is to do a little research and find what guilds on your server (or if cross-server guild), find which is best suited to allowing casual players to do dungeons, and apply for an invite.
Regarding Arah, the reason why you probably don’t see it on a third party random party matchup site is because Arah is considered to be hard enough that people just don’t like forming random teams to do it.
I would like to see a mystic forge recipe in the future though, haha. Maybe 250 stacks of any dungeon tokens x 4 turns into a stack of 250 redeemable tokens which you could take to a specific vendor and he turns those new tokens into whichever dungeon tokens you want. Thus, it would take four times the work to get specific dungeon tokens, so arenanet would probably be happy that doing the actual dungeon itself is more preferable than converting tokens. 