On Patreon this month, we voted for what to add in the May update. Anyone can vote. There was a tie between icebergs and the rearranger. So we did some of both. There is a rearrange day now, but no item you can use any time. There's icebergs now but you can't just make a bunch of them.
Creating your own icebergs was found to be too powerful. You'd always want to make a full row, and it would also change the look and feel of the game too much to where you're always seeing a full row of icebergs up front of everything when playing and when viewing someone's board. There needs to be a heavy cost to making an iceberg so that you don't just fill the whole row every time.