While I think getting slides in on time is great for a lot of reasons, reading the slides early isn't that important. What is important is that remote people see the slides at the same time as local people. For that, it seems to me that Meetecho support does exactly what is needed. You just follow the slideshow online, along with the audio. Of course, in order to have Meetecho support, you need the slides in advance of the meeting, preferably far enough in advance that it doesn't create a massive hassle for the Meetecho team. But by making Meetecho the place where the slides are presented, you ensure that everybody is on an equal footing, without engaging in punitive behavior. The main reason to want to see the slides in advance is so that the working group chairs can evaluate them to see if they will actually be a good use of time. But that's completely orthogonal to the remote participation issue.