I normally avoid topics like this as it makes little sense to me to speculate on cards WotC hasn't and likely will never print. That said, I have a question for the OP, @dshin: do you believe that printing overpowered, difficult to interact with hate cards for certain strategies leads to more interesting gameplay? Because I don't believe that. It turns MTG into the card game War with better artwork
I agree with you 100%, and I proposed the card I did as a reflection of that principle. I think hate cards should require skill to use, and that there should be good, interesting ways to interact against them. I honestly can't think of many hate cards that exist currently that beat my proposal when judged by these measures.
To illustrate some of the potential decision making - do you tap out to cast your Jace the Mind Sculptor, or do you wait for another mana source to keep your Hate Island live? Do you tap it to play your opponent's Gitaxian Probe when he also has a Mental Misstep in his graveyard, or do you permanently keep it up for that Misstep? As the opponent, if you have Mental Misstep in your graveyard, every one mana spell you cast represents a potential bluff, as Hate Island can only be used once per turn. That's a ton of nontrivial decision points that get created for both players, and the more nontrivial decision points that get created, the less War-like your game becomes. With delve cards or Snapcaster Mage in hand the decisions become even more complex.
By contrast, cards like Grafdigger's Cage, Rest in Peace, or Trinisphere offer no interaction - those are the types of cards that make Magic more like War.
I wonder if you agree with my overriding principle - that printing a strategically-rich hate card that makes it risky to run the blue cards that people are asking to be restricted might improve the metagame and gameplay. Again, not to beat a dead horse, but I think in the past Time Vault and Tinker were real problems - it didn't make any sense for any blue deck not to run them; this had a homogenizing effect on the metagame and made for uninteresting game play. This problem got fixed because those cards ceased to be as effective. And the reason was because of new card printings.