I'd just want to note that this DOES restrict your build to having an assassin secondary. That's fine usually, but you may wanna consider other feeder hexes for Discordway (see below).
Quick note: I'm not on my home Computer right now, so I'm salvaging the builds from GWPvX.
Ok, looking at your hero list, there's a two missing that might halp you: one necro and one rit. I'll assume, for the sake of argument, that you have gotten Razah (the rit hero from the end of NF), and not Xandra (the rit hero from EotN). Second, I would guess that you have not obtained Livia (N hero from EotN) I mention this because, quite frankly, necro and rit heroes are utterly pwn in pve. See if you can get these heroes: if not, PM me @ Portable Healy Unit and I'll provide healyservices.
I personally find running an MM on my character (i.e., not a hero) very boring, so see if you can relegate that to a hero. Heros are also quite good at managing minion support skills like Death Nova, so there's that too.
I recently completed yet another GWAMM on my Moldy Unit, and I pretty much ran one (brand of) build the entire time: an Icy Veins nuker with Discordway. As enter_the_zone mentioned, discordway is pretty much the meta for everything pve. However, it requires a quickly renewable hex and condition to work. IV works great here, as not only does it recharge quickly, but it also does damage on target's death (speeding up your kill rate). Skilling these heroes also isn't too nasty, since they all use the same elite (Discord, cap-able in Factions)
Now, what about your other heroes? Let's talk about rits. Rits are wonderful with their native spirit-wrangling abilities. Rangers can manipulate spirits somewhat, and there's one profession-independent skill, but only rits can really do as much with creating, maintaining, using, and destroying spirits. As such, I usually bring two rits:
First is an SoS/Resto rit (OACjEqiMJOXzyJGzbyMlmTuhJ is the build). This, along with the MM and heals from discord, completely replaces any monks. Poor monks. Please don't forget to feed your monks; they need love too.
My second rit is the ST rit, or as I call it, the "my monk is bored" build: OACiAyk8gNtePuwJAAA4MBAA. This build reduces incoming damage to very manageable levels (no nasty 600-hp HM spikes!). Remember that the spirits themselves are NOT under their own effects (i.e., Shelter and Union can lose more than 10% hp per hit), so it's often a good idea to watch where your hero is plopping these down. The optionals here can be energy management (Signet of Creation, mez interrupts, etc), more utility, or speed boost.
I'll finish with the final 2 heroes (Panic mez and Inept or Psychic Instability mez) later.