I think that a text only day might be a good idea, although I've never seen it done before, so I'm not entirely sure how it would work. I assume that during a text only day you can only post text links, but what about the front page of the subreddit (Hot)? Would previous day's non text posts be temporarily moved to help new text posts be seen? Or does that not end up mattering in practice?

Reading through the comments, I can see that there are some concerns that this would only limit the amount of content on the subreddit. Just to add some perspective to that concern, while it is true that reducing non text posts will reduce the overall amount of content, I think that is not really an issue unless you actively make an effort to read every new post that comes in.

I did a quick scan through the postings and counted that there were approximately 150 new posts in the past 24 hours, where today is a Tuesday. If you only read two pages (old style reddit) a day of posts under the Hot sorting option, then you read approximately 50 posts a day, which is only 33% of the content generated per day. Even then, this is assuming that every Hot post you read was posted within the last day, which is not generally true, and that every day of the week has the same number of new posts as a Tuesday, which is also generally not true and I would expect there to be other busier days. For these reasons, I suspect that 33% of new content being seen daily is an optimistic result. It's worth noting that the assumption of 2 pages or 50 posts read per day may not be the best estimate, however it serves as a decent test value, and finding the true amount of content read per day would require more data, which I don't have access to, and more rigorous statistical analysis (what is the statistical distribution of the content read per day? What groups of people read certain amounts per day? etc).