I disagree with a direction y'all are going here...
So, due to greater and greater permissiveness and mix&matching with less restrictions, "invincible units" started to proliferate as the new "sharp edge" of army evolution. Most armies lacked effective tools to make a game out of it when faced with an essentially unkillable unit.
There's two ways you one could address this...
A. "De-escalate": make it so that the unkillable units can't exist
B. "Escalate": come out with something that can obliterate anything automatically, even these formerly unkillable units. (this is what GW is doing, whether intentionally or not).
Both might solve the problem on the surface, but there is a difference in terms of what happens after that.
with option A, games go back to what they were before.
with option, B, you get games like this (PLEASE watch this everyone):
http://www.frontlinegaming.org/2013/12/06/welcome-to-the-new-6th-edition/Now, there is no competitive imbalance in this game in terms of who will win or lose the game. It was a very close game. But that's not the only metric we should be using to evaluate whether the Revenant titan is a desirable solution to the "unkillable unit" issue.
In this game, the Revenant killed both armies by itself. The only other model that was really relevant or did anything was Belakor, he possessed the Revenant to shoot at its own army. The other models could really have been anything, their only role was to get removed by the Revenant.
This game might have been (probably was) an extreme example. But can you see how, even if an extreme solution like D weapons solve a problem, it's possible that they might be a detriment to what we have been getting out of the game overall?
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aside:
I think that "non-degeneracy" was a key reason for why I originally started getting interested in 40k and less interested in Magic: The Gathering. I started to feel after a while that very few games of M:TG constructed were REAL GAMES. It was just sort of a contest of who could get their own broken thing off first. If you brought what you just thought was an "interesting" constructed deck, which didn't capitalize on some sort of recursive abusive mechanic, and you played against a competitive deck, you might not even get to cast any spells or do ANYTHING. If I'm going to put some free time into a game, I'd like there to be a really good chance that there'd be a lot of back-and-forth, nitty gritty, small conflicts that add up to a back-and-forth story - kind of like what happens in a well balanced board game, only with personalization.
It used to be that even if you brought a very fluffy army, you would at least usually get to move your stuff, shoot your cool models, kill some stuff, etc. You might get tabled in the end, but at least you got to PLAY a real game.
It seems like 40k has been getting less and less like that. It's not up to me of course, but I hope that the community comes together and forms a ruleset that makes tournaments more like tournaments more like they were before during 5th and early 6th.
