As Dies said, FFA is basically a 2v1, with the 2 lower ranked guys gunning for the higher ranked player. It's tough to win a 2v1, although it has been done. So as Dies said, you kill multiple foes, have seberal great card / unit combos, but lose the game, and then lose a ton of points.
This is my only concern about FFA rating. It really doesn't show the "best" player. I have seen FFAs where a persons first ever game wins with many high rated players only because he doesn't know what hes doing and the others kill themselves (not wanting to waste cards or mana on the new guy) to the point anyone can finish them off.
Maybe, what I propose is what you suggested last time. Remove Overall Rating. Keep individual ratings.
Keep the Overall wins/loses (so some acomplishment is felt) on "view profile"
and instead on the lobby version, have a title (based on highest rating), along with the wins/loses and rating of that game type.
Duelist <duel>

?? <FFA>
Teamster <team>
In team games . . . random heros and random teams . . . you can't strategize with a team mate . . . Obviously choosing team mates eliminates this as well as chosing heros, but many folks still play the random / random games.
Well, random teams is the only way people will play. No one will accept the "weakest players" (loosely defined) ranked or unranked. And the choosing of teams... no one wants to sit for 5-10 extra minutes to talk strategy.
Some folks are just so uptight and hung up on rank. It's just a game, if you play long enough, you'll know who the top players are. I've seen a player (to remain namless) playing ranked games against a complete newb. Sure he only was rewarded 1 or 2 points per game, but the new player left mad after the loses (and taunts), and I haven't seen him since. I checked the leader board and this new guy hasn't played since then. Not good for building the community! And for what, 5 points!
That is the point of an ELO system, that way a strong player can beat a weak one and barely take points. If the new person gets upset, they will get upset if they just lose. Do I think it wrong to beat up on a new person? Yes, but that shouldnt remove rank, anyone who gets upset with it would have been upset anyways. (P.S. after my 2nd week on here I was 950 rating, so anyone should know it is easy to turn around)
Also, with that said I run a code that I usually try to never play ranked unless it is someone I know is up for the game, has a certain rating in duel (IF i have never seen them before), or many games under their belt to hopefully know strategies. And Vin, I bet I can name the player you left nameless.
Also, some folks tend to play more conservative in ranked games. They get tense since it's ranked and "turtle up". But if folks are afraid to lose rank / rating points, they may tend not to experiment with different combos of units and spells since you're penalized heavily for loses to lower ranked guys.
That is why unranked exists, to try out combos, maps, learn the game, or play for fun. I enjoy rank, but enjoy the game even more. Also, if someone turtles up? thats fine its their decision, but a defensive setup is usually 1 of the easiest to break if you know how, so they wshould learn quickly once its being beaten to change strategies. Because in a duel (hint, hint) if I see a player sit back and wait, I already know I have a huge advantage and will probably walk away with the win.
Still, LUCK IS INVOLVED. Dice don't have a memory, you can go on a long losing streak due solely to bad luck.
Personal experience I assume?

The taunting, name calling, ill tempered, childish beavior just to see your avatar's name closer to the top of some list that is influenced by luck is just nuts.
Yes that is what annoyed me by the new brazilian comers, and the way they acted in games. (thank you google translator) And anyone who knows me I will not tolerate that kind of behavor.
But just one thing, the ladder isnt all luck.
Sure Luck is a major component, but skill does have its place. somewhere around the 65/35 line.
the way I think of a duel is a game is split into 100% to the 2 players whoever has the most wins.
---So if Player A is much better, he has all 35% of the skill, so all he needs is 21% of the luck, and he will win (needs much less luck, but it is still there)
--- But if the players are better matched say 20%/15%, than luck plays a bigger part. But the better player still requires a little less luck.
(This skill can be, knowing how to use your cards, when to save/dump, when to attack a hero or guardian, when to defend or attack, where to move and when, estimating what cards your opponent may have and if they have the ability to drop a hero to 0 in 1 turn.)
So that is what I have to disagree on, it isnt only luck. Luck is roulette, where a player has no chance to influence the game, there is great amounts of skill involved. I just agree, luck plays a bigger portion.
....this took longer than I thought it would