Your anecdotes pertain to Arena, in which you duel a dumb AI. In PvP, you'll find MA hard counters the majority of
![Time :time](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/time18x18.png)
monos. That's 8/12 elements.
Entropy decks very rarely pack BE, and if they do, they run into Lobo, which can cause summoning sickness and thus prevent instant use of BE. That's provided they even draw BE before they're beaten down since they won't be packing many copies. Discord does help with getting damage in before the Dim chain, but without dedicating heavily to BE+targets, there's still no hope. If you do dedicate to it, you'll be a lot slower (imagine sacrificing 6 cards to get PC) and might lose anyway, and you'll definitely lose to other decks.
Gravity might sound like it counters Aether, but once again Lobo takes care of Momentum. Extremely few Gravity decks pack backup Chimeras, and even then their chances are 50/50.
Many Earth monos do pack Earthquake, but it's not nearly as effective against a player. With 6 Earthquakes as max and a pillar/pend split of 7/7 for the MA, you have the choice of either decking the Monoearth out (if you win cointoss), or just beating them to death.
Monolife stalls are extremely rare in competitive PvP because they're just not good. It used to be that you could deck out a classic MA with ML stall 50% of the time (SoG's, Staffs and Thorn Carapace), but then came Psion and Psiontal. Emerald Shield does nothing since you can Lobo your own Psions, and Fractal easily overpowers the healing that was once sufficient.
Few Monowaters pack Trident, but those that do have a decent enough chance against MA. Again the pillar/pend split and slow-playing of them slows down the effectiveness of tsunami, but if the Monowater also has 6 Ice Bolts and some fast offence (Toadfish), it can get in enough damage before the Dim chain to finish off with Bolts. Chrysaoras aren't a factor due to Lobo.
Light can only hope to stall MA out, which doesn't really ever happen even in an unrestricted meta. Since this is monos vs. monos, Light has nothing. It can run Photons and Gold Dragons with Luci and Hope to try outstall a classic MA, but again there's Lobo, and again there's Psiontal. If we Play a Reflective Shield, out comes Lobo.
It might seem like Monoair has a good shot, and it -is- probably the best shot of them all in this mono vs. mono matchup. Unstable Gas decks are fairly common, so it's a reasonable comparison. This matchup strangely still tilts in MA's favour, which is something we've seen in War, over and over again. In theory it seems like Fog Shields, Dragons and UG's should have an edge, but in practice we see the Monoair getting rushed about 60% of the time.
Time has nothing. Literally nothing. This is the most one-sided matchup out of any mono vs. mono. For added hilarity, consider that Time and Aether are elemental opposites. If Monotime plays Etern to try to survive Psiontal, it still won't get to rewind enough Psions to stop the Dim chain because the Aether player just stops playing them and kills with Lobo and any potential Phase Dragon or Immortal it added. Getting to the HP range where Psions can finish them off is far too easy. Sundials and Procrastination only prolong the inevitable.
In the end, mono vs. mono is the last possible scenario you'd want to bring up if you're arguing -against- a Dim Shield nerf. Time and time again we've seen Monofires with as many as 4 Deflags losing to MA in War because they either don't draw enough of them or 6 turns of protection is just too much. Another way to look at it is this: Aether gets 6 turns of free attacks. That means Fire has to be that much faster about inflicting the damage. Kind of insane.
Of course, the classic 3 Deflag 6 Bolt Monofire with Phoenixes beats MA on a regular basis, but you also have to consider restricted metas like War, because that's where Dims have the largest impact by far. In Leagues you don't really see Dims all that often, which would speak against a Dim Shield nerf if it wasn't for the fact that the meta in Leagues tends towards rushes, rush counters and denial. This is why you see things like Monoentropy, Monoair, Monolight and Monotime in Leagues.
In closing, I'll clarify that the above argument assumes the common monos used for each respective element since MA is the common Aether deck, but for the sake of the argument I also included a part where the mono would be geared towards beating MA specifically. As I've stated there, even then most monos lose consistently to MA. The fact that they'd have to change their decks up a lot if they wanted to have a chance against MA speaks volumes on its own.
Dims are a meta-defining card in every environment as they remain the biggest reason for all decks to pack PC. This is why it's one of the cards we have to consider banning in every tournament that aims to create a fun restricted meta. A 2-turn Dim Shield would retain this position; whether you give a deck 18 or 12 free turns of damage doesn't matter much.
With all this said, I don't think a Dim nerf is the solution. I think more elements need viable ways to either beat permanents or stall better. Unfortunately our stall chances got slaughtered by the advent of Shard of Wisdom and Psions. That leaves us with one option. Soft PC like the time stasis for perms suggested in the Card Ideas and Art board would be fine. The only requirement to new ways of PC, soft or not, is that they're at least effective at what they aim to do.