Me too, it will just dramatically increase the size of the events. In my latest revision I've increased the truncation threshold by a factor of 5, but it still makes me a little nervous.

It's almost certainly worth doing for some fields, others (like "data" vs. "event") will have a much higher cost...

If we had a versioning scheme I would feel much more comfortable doing it, then we could end-of-life the other fields and remove them in the nearish future.