There is an ignore option that you can use, click the developer or publisher name on the store page, on their own page you will see a small gear icon on the right side, click that, the ignore option is there.

Originally posted by RJS:

Is there a way to completely block/hide a developer or publisher?

Like EA, games that waste clicks when I browse a game in the store before I notice the publisher?

You can already ignore dev/pubs IF they have a dev/pub page to ignore.

For EA... https://store.steampowered.com/publisher/EA

Click the cog icon to the right hand side of the page.

Some titles aren't associated to the publisher page and may not be ignored by ignoring EA themselves. And not all areas of the main store page may not respect the ignore.

Sometimes you have to refresh steam page to make the block/ignore works, unlike todd howard...it just works