I'd love to see WOTC split the product line into booster packs for drafting and something else for collecting/constructed.

1) A category cards aren't "metagame staples", they are just overwhelmingly good for a given archetype. I mean, Lightning Bolt is A card for every red deck in Modern, Inferno Titan is an A card only in red big creatures decks, and Stone Rain is an A card, but for only one archetype.
2) Bannings help, but they are like helping your irrigation system by spitting on earth. Due to the nature of a bell-shaped curve, the optimal amount of bans in a format is... 50% of the card pool. LITERALLY 50%. If you ban the upper half of cards in a power curve, you get the biggest variety of playable cards, because "playable" becomes equal to "average".
Limited is no better then Constructed. In Constructed, you can experiment and lose. In Limited, you can't experiment at all. It's like poker - a game of evaluation. Only good when you're drunk, and the stakes are insane.
The solution is clear - flat, FLAT power level. It is hard, because ANY card significantly better then the cap is not just an A card, but also a source of a dominant deck and a format ruinator. But there is no easy way of creating a balanced game with 1000 moving parts.

Constructed demand creates the market that helps offset the price of drafting. Without that, many people would draft much less. It's not logical, but it works for the same reasons that make people buy lottery tickets.

We've now had at least two blocks where experimenting in Limited was doable, and even profitable at the beginning of the format. I still remember fondly decking people with Fleeting Memories, and playing a sealed pool with Aethersquall Ancient, two Dynavolt Tower, Aetherworks Marvel, and tons of red removal. The whole Vehicle thing was a big experiment in evaluation and deck construction, spawned a lot of debate, provided some valuable new insights into Limited play. At first, everybody was enthusing about RW aggro vehicles being the thing to beat in draft; then BW was the big dog; then people started winning with classic control decks featuring Minister of Inquiries as the win condition. Even now, with Kaladesh limited more or less explored, people still manage to draft and win queues with surprising decks.

Which brings me to your second point. A flat power level would kill the game in short order. The exploration of a new Limited format is why I play the game. Evaluation is an essential skill for Limited Magic, but it's a very different game than poker. In poker, you play the players, not the cards; in Magic, you draft to your strengths, thus raising the power level of all decks at the table, and making life interesting.

Yeah, I don't understand your critique of limited at all. You CAN experiment, but it's definitely a gamble, because you never know what cards get opened, even if you can accurately guess how they will get passed.

MaRo talks Frontier:

The Casual.

I don't follow.....Commander was a Casual format created for casual reasons. "Frontier" is meant to be a competitive constructed format that isn't Standard or Modern.

That was a joke.

hard to argue over that.

banning fetchlands would look even worse, unless they used the "matches take too long with them" rationale

Yeah, but fetch-lands come at a barrier to entry cost and allow for easier builds of "good stuff" decks that mine from more colors.

I expect that, if Wizards is going to jump on a new "Post-Modern" or "Frontier" format to bridge Standard and Modern, they'll probably do it around 2020 and start the cut-off at Origins. By that point there will be about nine blocks to choose from with a diverse card pool, all designed under the two-set model. I assume that, in order to keep the Modern crowd appeased with certain reprints, things like fetch-lands will just end up in Modern and Legacy Masters sets from here on out.

Waiting until their are enough sets post Khans implies that they are not going to reprint Zendikar fetches in standard for a long, long time.

The price of Scalding Tarn is one of the top 5 reasons modern is so annoying. I guess they could print them at uncommon in EM2/MM3, that would be pretty hilarious. Maybe rare is OK, drop the zendikar fetches from $80-40 to $20?

I'm reasonably certain that Fetches will never be a Standard thing ever again (outside of the rare Master Piece/Expedition lottery). There are now other avenues to reprint them to help ease demand while making tons of money and not overly influencing the singles markets that LGS venues depend on.

Rare lands are sooooooooooooooooooooooooooooooooooooooooo st00pid. They are among the dullest Rares, but also among the most expensive...

a post-modern format would imply that modern would be functionally replaced, because the game can only really sustain one non-rotating format

but yeah that is probably the cutoff to choose

Well yeah, Modern would become the new Legacy, played only by those with real money or well developed collections, and Legacy would be a thing that collectors do for fun in their basements or conventions, playing around with cards too expensive or rare to reasonably field a tournament for, like Vintage is now.

No, modern would die. I don't think WotC can support modern and frontier at the same time, and I don't think people will play modern after WotC drops support for it.
Replacing modern with a new "modern" doesn't constitute a new format, it constitutes a rotation combined with a name change.

I think I would continue to play modern if WOTC dropped support. I stick to non rotating formats and I missed the boat on legacy; no way I can afford a ticket now. Modern dodges the weirdness of the game\s early days while keeping the card pool deep enough that I can find wacky stuff nobody's done before. A new format will need more sets to sway me.

I'm wondering, would there be a way to have a format with a longer rotation that doesn't have the same problems as Extended had. That would be more likely to attain the stated goals of Frontier.