Andrew said that they would be abused for farming. So I don't think this will happen, as much as I would like to see it on ecc, it is way too powerful. So my vote is a no.
Beacons could cost a lot of money and everyone would want one, wouldn't you? With everyone buying beacons the market would go up, and nether stars could be obtained from rare drops of excavation aside from Withers. Even know haste means breaking blocks faster, its not very overpowered because it doesn't cause a huge increase in speed and only eff V wielders could take advantage of this majorly.
That is the problem. With anvils, eff V's can be obtained easier than before, allowing the users to have a very unfair advantage.
I've tested, and it does go much faster. It insta breaks melons! So, double what you make pumpkin farming, and there you get 30-35k per hour
