I have noticed a similar trend in a different setting: highly technical parts of computer science, in particular POPL-style approaches to programming languages, and ISSAC-style symbolic computation. But there also arises a solution, of sorts: people's proceedings papers are precise, often dry, and full of details. The good presentations of the same material at a conference will typically involve a lot slides for motivation, the big picture, worked examples that give the general idea, and so on.
In other words, the proceedings paper alone is dry and only cursorily motivated, while the talk slides (on their own) could be seen as fluffy and imprecise. And yet, if you take both together, they give an absolutely fantastic view of the results. There is thus an increasing trend for computer scientists in these disciplines to post both their paper and their slides on their web page -- because each gives very different aspects of their actual contribution.
I like this style. Is there a way this could be transposed to mathematics?