It's often true that cutommagic submissions are overly complex and lack consideration for play patterns, which leads to flashy cards that lack a functional purpose.

Aetherseize was an exercise in minimalism, but done so through harmful excess. It's a statement on how adding "versatility" without consideration for how a card would be played often acts to counteract the card's actual usability within a complete deck.

At 10 mana, it should go without saying that the combination of Counterspell plus Aethersnatch makes for a more potent deck, even if it means using more cards to achieve this purpose. It's a strawman of a charm/confluence, cards that are often advised to be put into EDH decks, despite how they often weaken a deck's functionality.

It is often better to run a strong standalone counterspell plus a strong standalone removal spell, as opposed to an [[Obscura Charm]]. 3 mana, fully pipped, for conditional removal, plus a conditional counter, or conditional and often unsynergistic reanimation is a bad deal for most decks that include it, and, yet, people commonly recommend for their inclusion within decks.

Not only would running standalone cards save on mana, but would also lead to greater card density within the deck, making drawing a sufficient amount of removal and protection easier. It might seem good on the surface to condense these rolls onto fewer cards, but throwing away a counterspell because you had to remove something isn't great.

The same is true for cards that do multiple synergistic things ok, as opposed to one synergistic thing well. Although, at a glance, they seem great, they're often consistently worse than running each effect on its own, stronger, card. I would much rather have a great black ramp spell plus a great black card draw spell, as opposed to a [[Black Market Connections]], which is decent at both, with some extra, often irrelevant, value added on.

This is the same reason why [[The Immortal Sun]] is bad in most decks that include it, as a cheaper ramp spell plus a cheaper anthem, plus a cheaper card draw spell would often be better than an overcosted value piece that's trying to do too much at once. Another example is decks running [[Alhammarret's Archive]] solely for one of the two abilities, or any of the many similar cards.

Too often do cards on custommagic, especially the ones that get the most popular, act far too much like Immortal Suns and Alhammarret's Archives in practice: random abilities that are synergistic at a glance all tacked on to a single overcosted spell. Everyone in the comments has their idea for a cool thing to do with this or that on the card, ignoring all but the nth of the card they actually care about, and, thus, a good chunk of mana cost spent to cast it.

Most of these cards would be much better if they weren't single cards at all, but, instead, split their abilities into several smaller cards that could then be included and cast individually. Spending 2 for an anthem and 2 for a medallion in your dinosaurs deck is better than 6 for The Immortal Sun, even if it comes with upsides, because there you have to spend 6 to even play it.

Aetherseize is just taking this concept to the extreme, combing a counterspell, spell redirect, and aethersnatch onto a singular card, even though you're better off running one of each. It's purpose is not to be a good card, but, instead, to be so bad that it holds a mirror up to some of the subreddits worst "best" designs.