When/if: an artifact that "turns off" when it's tapped, like howling mine or winter orb? I know it's a holdover from old rules about continuous artifacts, but I wonder if there's any potential design space with it.

If. It’s not particularly fruitful design space.

You mentioned that white can get effects that draw over time, like dawn of a new age or four knocks. Does that mean white could get “at the beginning of your upkeep, draw a card”? Or does there need to be some other condition that controls how much drawing gets to happen?

We’ve chosen not to give white Howling Mine straight up. The numbers of draws are limited or you have a hoop each turn to jump through.

the oracle text (at least on gatherer) for various copies of the roller coster calls it the "roil coaster" in every flavour text eg "The Roil Coaster moves faster than the speed of sound." whereas it has different names for each version of the printed card eg "The howling mine moves faster than the speed of sound." I don't know if this is your domain but why is this?

The Roil Coaster is one of many roller coasters at the Astrotorium. It is the biggest.

Could white get a card similar to howling mine/temple bell?

No, that style of design leads to gameplay we don’t want in white. White’s group draws are one-shot and not ongoing.

Since white is getting access to flash, could white get Dictate of Kruphix?

White doesn’t get Howling Mine.

Would you be OK with giving Howling Mine to White? Blue usually does shared card draw, but it's not something Blue doesn't us it often anyway and sharing is way more White than Blue.

It’s being talked about.

Chance of getting a Howling Mine or Howling Golem colorshifted to white?

We’ve been talking about whether or not it properly fits with everyone draw. It’s being discussed.

Regarding your time travel article. Would you do a two mana howling mine enchantment in blue to shy away from the original? Or would you not, as it is just a worse howling mine?

In my alternate world, Howling Mine would have just been a blue enchantment (with a different flavor). Being blue would make it different, not worse. You could discard it to cast Force of Will, for example.

So I am not particularly bothered by the colored artifacts being like enchantments, but why not feed into the tapped distinction? Accept that older artifacts like howling mine are grandfathered in, and now say artifacts can’t have static effects? Or maybe even just bring back the old mono artifact rule if you want to add static effects? Now seems like a good time to rehash the question you mentioned came up in Mirrodin.

If I couldn’t win the argument with inertia of ten years, I’m not winning it with the inertia of twenty-six years.

Glass Casket has me concerned. It feels like, ever since colored artifacts became an every-set thing, there just aren't that many mechanical niches for enchantments anymore. Artifacts get to also be creatures, cost generic mana, have tap abilities... the list goes on. The only thing enchantments can do that artifacts can't is attach to objects other than creatures you control.

Artifacts have had global effects since the game began back in Alpha (Ankh of Mishra, Black Lotus, Copper Tablet, Dingus Egg, Gauntlet of Might, Howling Mine, Kormus Bell, Meekstone, Sunglasses of Urza, and Winter Orb). The change is we’re allowing artifacts to have colored mana costs (and even this we’ve done for over ten years - just not at the current levels). This means the overlap between artifacts and enchantments, which has always been there, is a little more noticeable.The color pie is determined by the mana cost of the card, so if white can do something as an enchantment, it means it can do it as an artifact, The result of this is we have to lean a little more on the flavor to help make them feel different from one another.