They should consider to put some alpha maps from the community in the 'Beta testing', I'm pretty sure it could be a really good move from both parts, the mapper have a lot of informations, and maybe a lot of feedback, while Valve does nothing but get some good maps from the community, and everyone is happy.
Of course those maps have to be really serious and the mappers have to know what they are doing.[...]
I find this very unlikely to happen.
I'm going to roll this up the other way around and start with your last point and work my way up.
With all seriousness of EOTL and the high degree of professionalism of the people involved which may or may not be true to some extend (but in comparison, in terms of an officially promoted update it is as serious as it gets), the public reception and Valve's was bad. I'd like to separate that into two parts, content-wise and marketing-wise:
Content-wise:
The map was cut. Without the map it's basically the crates, the duck journal and a few weapons (if I'm not mistaken). Gameplay-wise it didn't add anything more than some smaller update Valve pushes that does not only include fixes.
There's different opinions about the movie, of course. Some like it, some don't, the youtube comments had some further elaboration of some in-depth technical stuff that could have been improved animation-wise (which I cannot evaluate since it's not my area of expertise). Personally I would have loved a more close collaboration with Valve and getting the voice-actors in on it, because for a non-verbal-dialog movie it didn't fully utilize the potential of those silent moments and nuances where the viewer draws his own (funny) conclusions to certain scenes.
Marketing-wise:
In my opinion this is the part where the most potential was thrown out of the window. It was ridiculously overhyped, and the map was even leaked.
It was just milked out until nothing was left. I think McVee could have improved a lot in that department, especially if he wants to utilize this as a reference for his later career.
Concluding with your first point:
Since EOTL was unwillingly beta-tested and not good enough in Valve's opinion, I find a further collaboration in form of officially pushed betatests of community maps unlikely to happen. Also, after all, this is what tf2maps.net is for. On that note, TF2 already has enough official beta stuff going on.
For Valve (also due to the general reception of the update) EOTL was a failure/disappointment. It left such a bitter aftertaste in the mouth of the community that Valve had to push another beta thing (the mannpower gamemode) to over-color it. A gamemode, that is insanely difficult (I would say impossible) to ever properly balance out due to the huge number of weapons TF2 already has. It hasn't even been teased or hinted at with leaks of code or anything which is very untypical for Valve, indicating that this is quite a desperate move. However, I think they have avoided that EOTL-cliff for now, so this was kind of a smart move.
[...]That's the best compensation imo, your map is played, Valve see if the public like it or not, and then they can buy it if everyone like it.
Imo you're all talking too much money there, the best compensation for a mapper is to see their map played and enjoyed, money is a good plus, but it should never be the first incentive when you make a map.
I second that. If I take a look at other modding branches, the complexity of the projects, their value to a game and Valve in general and the public reception and recognition of the branch in total, I think this thread comes off as insanely arrogant. I'm not interested in further elaborating on that, as a community specialized on a specific modding branch is a very bad place to have an objective and well-moderated conversation on this particular topic. I'd rather have this further discussed on gamebanana, facepunch, or hell even spuf where modders are either a fraction of the community or well balanced onto different branches (equal parts modelers, scripters, mappers and whatnot).
[...]Players and many server owners dont actively search for new maps, they often just hear it from others. So if valve would mention a map and not even add it to the game many servers owners and players will still notice it. And when players as they are more likely to play it (unless its a 100mb map which makes the filesize the showstopper, a 30mb map is accepted by many).
They should. I'm guilty of crawling a huge amount of servers for information (player counts, maps played, and how often they're being played etc.) and as soon as something new is being played (db or ph-wise) I know about it.
Many (if not all) community admins have alliedmods accounts where they look out for the latest plugins and seek help. That's why I think it is the job of this community to promote mapper's work and offer an interface to other communities who would potentially want to host new maps.