This has
been suggested
quite a
few times
in the
past, and yet has gotten nowhere. The end result of which is exactly the situation we find ourselves in: Rune Shards are now actually worth something more than just a thing to bust apart for broken shards. I even had a
not-so-pretty mockup of such a suggested feature after explaining/discovering that the "Research" and "Rune" tabs in a given Ancient Wonder are mutually exclusive.
There's also the highly confusing yet oddly precise terminology involved. "rune shards" are the thing you insert into an AW. "broken shards" are the thing you use to forge said rune. Maybe reword your post to make it clearer what you're talking about?
Running a search on "broken shard" and "rune shard" in just the "Archived: Ideas and Suggestions" forum reveals that this is a problem the devs continually ignore.
EDIT: Alternatively, try formatting your post to use
this guideline if you want any hope of your post making it past the first step in getting it heard by the devs.