Frasier - Season 11 (that's right, 11 - the final season) arrives on 9/21.
After that release, Paramount is expected to go back to in-order releases, picking back up at Season 4. Expect that to take several months to get to, though.
As for Mad About You S3, noone wants that more than I do. But Columbia wasn't satisfied with sales of S1 and S2 enough to prioritize the 3rd season. They've put it on the back burner, until they get out some different series which they expect to sell better. Customer demand will help them prioritize that again, so let them know! Use a search engine to find contact info, and write to them. Be polite; they won't listen to rudeness. And don't tell them I sent you...just politely say you're a consumer who wants this, and got it into your head to ask the studio when he'll be able to buy it.