As a side-note Black hole also means you can't sacrifice to get out big guys straight away, doesn't it?
This is a bit off topic, but...
Thing is, most of the time people would Special Summon their big guys anyway, or they were relying on their enter-play effects, etc. Or they might have a Monster Reborn or something to summon it from the Graveyard anyway.
In my opinion, the game was sort of fun, "kid" oriented or otherwise, but it's only somewhat close to "balanced" with a long list of limited and banned cards, or through limited formats. Speaking of which, I do hope that Team 5 will keep a window open for more limited formats in addition to Arena. I think (among a bad business model and other issues) one of the reasons that PoxNora, an otherwise very interesting, high-depth strategy game/TCG has is the lack of limited formats. Since it's been around so long, it means it's very hard for new players to get into, getting staple cards and such, or even figuring out what they actually want to play in the first place.
But that's a long-term issue, and obviously nothing needs to be done about it for HS any time soon.
****Back On Topic:
I've said this in other threads, but someone (not me) made the suggestion of gaining life for each killed minion. I think this would be a great way to improve Twisting Nether's value.