Requested feature overview description.
Put some help text and a link to MetaSearch and the BUR search on the new-alias, new-implication, and new-BUR pages.
The text might read something like this:
Tip: Before requesting a new alias, implication, or BUR, check the tags involved on the MetaSearch and the BUR search.
If those searches show a pending alias, implication, or BUR that is the same as the one you want to request, don't create a new request. Instead, go to the existing thread and upvote it, and (optionally) post in that thread to bump it to the top of the forum.
If those searches show that the alias, implication, or BUR you want to request was previously proposed and rejected, go to the existing thread and see what reason, if any, was given for the rejection.
For aliases and implications, the help text might also need to cover the case where a previous proposal was rejected in a mass rejection. In that case, it might be okay to either propose the same thing again, or go bump the thread where it was rejected and ask for it to be reconsidered.
Why would it be useful?
Some newer users, and even a few experienced users, seem to be unaware of the MetaSearch and BUR search pages. Giving them a hint about those pages may allow them to find out that their proposal either already exists, or was rejected for a good reason. This would hopefully result in fewer new aliases, implications, or BURs that require user and staff time to say "That already exists" or "That was already rejected because...", and reject the new item.
Something like this kind of already exists. If you propose a new BUR that has elements that duplicate or otherwise conflict with an element of an existing or pending BUR, you'll see the # problem note on the problem line(s) in the new BUR once it gets posted to the forum. It's not clear to me that the new BUR will check existing "bare" aliases and implications for conflicts, though.
If the proposal to integrate MetaSearch and BUR search is implemented, the help text would need to be changed to link to the single search.
What part(s) of the site page(s) are affected?
The new alias, new implication, and new BUR pages.