Yes, but there would be blocks underneath, after all, the 'Ever Changing Block' is a surface-based block.
I personally love this idea And you wouldn't be able to mine the block and place it again just to wait for it to change to something rarer, because you get the block you mined Also, though, things like exploding blocks would mayhaps be a problem because if they automatically exploded, it would explode and destroy the block There would of course have to be limitations to what it could change to. Also it'd be cool for it to turn into a water-spawning block and just randomly let out a nice gush of water, only to stop in 5 seconds. *cuewtfmoment* You have my vote!
It's very nice of you to post feedback. I think exploding blocks will be one of the most rarest blocks to change to, if not, gotten away from being one.
I quite like it - but it would have to switch a lot quicker for me, every 0.5 secs or so. Then if you choose to mine it you would just get one block of whatever it finished on in your inventory. Would have to be isolated and not in groups as well. It reminds me of having a single demonite ore (useless). So as a novelty idea not bad.
here's a thought how about this 'Randomite' ore when first discovered covers only the few basic ores that are most common on the planet it's found on but once it makes contact with other ores via first being mined then place or a block placed in contact with it the ore remembers them and adds them to it's cycle e.g. Randomite Ore cycle: Gold, Iron, Copper Randomite placed beside Aluminum ore changes cycle to: Gold, Iron, Copper, Aluminum and so on