The only thing smogon will ever retest is possibly aegislash. (banned by a 62% majority, you need atleast a 60% majority inorder for something to be banned.. litteraly 1 vote caused him to leave, and many unskilled players easily laddered during that test, and the voting period even ended earlier than it should have as people were changing their votes.) No body has really seen that big of a meta change after his ban.. except for maybe mandibuzz losing viability and gallade, pinsir, and heracross destroying stall. I've heard talk from the council about a "potential" retest there but nothing too serious.
Mega Lucario on the other hand.. it was just too much, it has overkill stats all around, can run special, mixed, or physical, good coverage, might as well argue regular rayquaza to be dropped to OU. The metagame did indeed change, but not at all for lucario as he still nukes everything with adaptability. He's a Mega Beedrill with larger verstility, equally versitile on the special side, higher base power moves, better STABs, priority, and better typing/bulk. That's not even mentioning nasty plot+swords dance.. Sorry about that is a retest I don't believe will ever happen. Unless a new generation comes out with 50 or so checks to him.