I've looked into the discussion and I agree in general that maps with a lot of custom assets (and therefore take up a lot of bandwidth) is more damaging than good for ladder. Solely because it can cause a match to appear to be stuck for the majority, where as a single person is still waiting for a download to finish. And since my aim is ladder, I need to change my approach.
Another issue that I want to mention from the mapper perspective is updating the map. E.g., if I want to make a minor change to Autumn (add the cliff build locations) I immediately add 200 Mbs to the server and everyone's personal storage. On top of that - all those people with a slow connection have to download essentially the same map all over again.
@harzer99 thank you for your suggestion, I was not aware of the size difference. It is quite large in practice. I've been able to reproduce them with Gimp. Sadly though, I can not reproduce it with my automation pipeline and therefore it would involve a lot of manual labor near the end of an iteration. Therefore I can not make use of it. In practice, when a typical 10x10 map is 5 Mbs, reducing from 80 to 50 Mbs per texture is still not sufficient anyhow.
I've decided on doing the 'you can download the HD files yourself' approach as that is the only reasonable solution to the problem. Any other solution is essentially asking someone to solve the problem for me. I'm not entirely sure how this will take shape. Do people have suggestions for services that can store and make available relative large amounts of information (think in terms of 10 - 100gb)? I was for example thinking of making it part of my website to cut costs through my company - but that is less community friendly especially when other people join in on the journey.
@FtXCommando I think you need to add in a map-size limit to the ladder selection. I'd personally not allow any map that uses more than 50 Mbs, as that can already take more than a minute to load for someone with a slow connection. I noticed this during the testing for tmm when a map of 38 Mbs was chosen and people were already wondering if things were broken. In practice without having BlackYps telling you that it has nothing to do with the matchmaker it may cause the entire match to dissolve before it starts. I don't know if it would be difficult to add in, but maybe a similar message in the client when uploading a map stating that anything above 50 Mbs is not appreciated in general.