okay, short questions:
How many games should you play each month?
How many cards should be legal each Season?
How much time should be available to figure out a deck before format change?

I think expecting someone to play 4-6 matches per month is reasonable.
If you're trying to emulate a type of standard (low barrier to entry) then about 1000-1200.
About a week or so if at least 1 set is the same.

3-4
~3 blocks
The new format should be announced 2 weeks in advance

But we can't do blocks.

My advice

The Format starts with two of our 3-set blocks, plus NGA Masters. When rotation occurs, the leading player nominates one set that wasn't legal to become legal and the last place player nominates one set that was legal to become illegal.

The problem is that there's a very large power differential between sets. If NGA Masters is ever in the same format as The Exterminators, it's basically going to dominate Constructed and push EXT out of the format. If we're going to do a rotating format, we should be willing to make large changes to the rotation so that these lower-powered sets can see play.

Yes. I do think that there needs to be some part of consecutive formats that stays the same to lower the barrier and have a stable feel.

I really don't know if that's possible. Even the difference between Fleets of Ossia and The Exterminators is pretty big.

If you're concerned about accessibility, how about tweaking the format rotation to favor smaller formats? We can do something like two seasons of 2-3 sets interspersed with one crazy wild card season, like Eternal Singleton or Riorvard Standard. Alternatively, we can start with just a few sets, then build up over each following season, until we reset and start over with a new league.

I think we might need to push the set rotations in the right direction a little bit. Eventually we want all the sets to have a fair shot at getting played, but in order to shift the format from one where Ossia block can have its day in the sun to one where Solphos gets played there would need to be some intermediate steps. The entire format would need to gradually step up or step down as it rotates, and that implies that there's a bit of planning behind the scenes.

We can pair by power level if it's really a concern but honestly if you look at Standard formats in real magic even when you have a powerful set/block combined with a weak one the weak one still dominates at some point simply because it has more cards in it but also because the card pool is so small. But at the same time something like the power level ranking I put up should help create more equitable standard formats.

It'd also be neat to look at synergies between sets, like BCP4 and Stormfront's shared "vanilla matters" themes. But compiling a list for all existing sets is way too big a task. Better to worry about that on a rotation-by-rotation basis.

Choose a bunch of cards from the exterminators that you want to be constructed playable and ask me to knock 1 off their cost

Nah, to be honest exterminators has some powerful synergies (bird tribal looks crazy) and I think even with other sets it'll still be constructed playable for a pseudoStandard.

And yeah, Mown and I had discussed looking at synergies between sets and blocks and I want to explore that but I think we'll naturally move in that direction as players explore the format and if the players half intentional self directed rotation then we'll get that naturally.

You can't really have the same speed as standard rotates. We get new sets as a much faster rate, and we also have a massive backlog of sets that wouldn't have been in a format, which I think a lot of people will find unfair, since they could easily never be chosen.

I think that we want to change at least 2 blocks worth of cards between each rotation, both to be "inclusive" and be able to fully experiment with what we have available.

I think current Standard worth of cards if fine, and 2 weeks of preparation seems reasonable to me.

also, this is my Ossia invitational card.


I can't really settle on a name.

Likewise.

It's probably more constructive to ask here instead of the metaboard, now that I think of it.
CKY, could set denominators for overlapping card names use parentheses or squirly-brackets instead? You can't do [nc=cardname] with them because it breaks the bbcode.

Sure, I can use parentheses.

I wish I'd paid more attention to duplicate names; they're more trouble than I thought. I feel like I should fix Arrow Storm and Turn Against (even though they weren't duplicate names at the time I made them). Throw Down (previously known as Knock Out) is fixed now but missing its flavor text... Blah, it offends my sensibilities, I should have been more careful.

(Also, if possible I'd like to change the name of Æther Riptide, based on the fact that WotC has realized the Æ ligature is dumb.)

I like Æ, dont dumb down magic more.