I appreciate the devs making sweeping combat changes; gone are the days of the 1 shot MK opening kills, where PvP was all about whose MK or Koros could go off first.
However, I believe the devs overshot the mark with the release of Goretusk and the damage reduction adjustments. Though it is now impossible to achieve 100% damage reduction, the developers have made it much easier to hit the 90% cap and stay there for a good portions of the match. When you're talking about big hitters vs. full DR, you run into situations were a full attack Rogue DP focused Shade, is doing about 3,000 damage to a Hopper who has an estimated 12,000 life (i.e., would have hit for 30,000 if no DR). Yes, you can focus on GT first, but in so doing, you open up your team to the other toons, namely an attack-runed Zomm or Hopper, which will cripple your squad in a turn, two at most.
In general, runes balance themselves; Destruction/Aegis runes will end up with the same % of Damage Reduction/Penetration, etc. The issue is that, as far as i know (level 68), there are no heroes that provide a damage penetration passive, while multiple heroes provide a damage reduction passive.
The main issue, of course, is Goretusk, who provides a 75% DR passive to begin a match, and even at 6 momentum ends up giving out a 15% DR. Combined with rune passives, opponents will start out with 125% DR, meaning that you need to reduce GT multiple times to have a chance at lowering the 90% collective DR. (anything over 90% DR gets reduced to 90% DR, so hitting GT a few times to get him from 75% to 50% just means total DR went from 125% to 100% . . . .which BOTH get reduced to 90%, meaning no effective change).
I think the only way to counter this is to adjust current heroes, or add a new hero that provides damage penetration as a passive. At a high level, the options are to either go full attack, and hope that you can kill their GT, Lily or Hopper before Turn 2, or try a damage reduction strat yourself and win a 10 minute war of attrition. Balanced heroes have almost no place; runs are either 4-1 Attack/Defense or Defense/Attack oriented.
The other option would be to reduce the Mammoth Guard passive to only last through 3 charges, going from 75% at 1, 50% at 2 and 25% at 3, with the 4th momentum charge removing the passive all together. The fact that you have to focus on a fast tank for 6+ hits before you can legitimately wear down an opponent is just too far the other direction.
Sorry for the novel, just getting frustrated with the unbalanced META at the moment and wanted to provide a constructive solution rather than just throw a tantrum.