**disclaimer, this post is based on my limited knowledge and intuition. I may be completely wrong**
@Snowbat
well, jpras is sort of doing curation for the workshop collection. But I imagine the only thing they want to keep out is everyone's back catalog of barely fitting reskins from 2012 that are getting rebranded for mayann. I don't think we need to worry. Even if somehow your map doesn't make it in the collection, I'm sure valve will take notice if it is a standout. There's only so many maps to go around. The way I see it, the collection is more of a suggestion list.
Now, here are my feelings about mvm maps.
Mvm maps kind of are a different beast since mvm maps have their own monetization model. While there's no real reason why mvm maps should be kept out of the update, there's a couple things that are worth considering. For one, I'm not entirely sure Valve has figured out the nitty-gritty of how they want to handle community mvm maps but the good news is they probably gave it some thought with the event of Iron Gauntlet. I have very little insight on what Valve is up to, but I'm going to guess that this is the problems they are facing.
Splitting mann up ticket revenues (and possibly surplus vouchers) is very tricky, even if it sounds like a simple/obvious solution. The perfect model would be to get revenues from mannup tickets used on your map, that's just what makes the most sense. It makes sense for mappers, it makes sense for players, it's something that should just work. Unfortunately it's not all that simple, mann co store revenues are always split upon item sale, not item usage. That's part of the reason why we have a stupid amount of different keys, you can direct a key's money toward the community crate it opens upon its sale. If all keys are just going to be the same price, we should really only have one key for all crates but the system is set up so revenues are split upon item sale, not usage. That's just how things are atm, and I'm of the opinion that the user the user experience for the consumer is suffering from it. If mann up tickets were to follow the trend set by keys, that would mean community mvm maps would each get their individual tickets. Can we agree that this would be utter madness? getting a team of 6 people, each with their ticket, is already enough of a clusterfuck. On top of that, the mvm lobby system simply wouldn't allow that to happen. Imagine voting for what mvm map you want to play, welcome to literal UI hell. Maybe Valve has a solution, but we haven't seen it yet.
The alternative solution is to act as if the map was just part of the community update/campaign and just ignore the mann up money. The fairness of Valve getting all the mann up revenue would be debatable but I'm not going to go into that, could be that mann up money is not even sustainable, I don't have the data. Ethics aside, I'm just going to say that it would definitely feel like a missed opportunity at getting map monetization right.
With all that speculation, all I can say is that Valve has some figuring out to do and that they might not be ready to accept community mvm maps. It then becomes your burden to convince them that your map is worth their effort. It's grim, but if I had to guess, I don't think they'll sink their teeths into that until matchmaking is done. But don't let that stop you from making a great map, go for it and give it your all.
godspeed