I'd love the ability to choose 'Query String Variable' from the CMS filter by list. 

Filter [field name] [= , > , < , LIKE ] [enter your variable name]

Then on the link block or link panel, add the ability to add query strings from the CMS collection. Choose any page or external URL for the link, plus add [enter variable name]=[field name]

Would be even better to be able to keep adding these variables with AND or OR

My filter would be:

Filter by [category] = myQueryStringVariable AND [post date] > myDateQueryStringVarible OR [featured] = IS SET

It would really open up a lot of search / custom pages / templates etc.. !