>>31634679Only Latios gets strictly worse, Latias is a sidegrade. SubCM hasn't been good since Gen 5 but Mega Latias can still do the offensive and bulky sets fairly well. Generally, you would stick to regular Latias if you wanted to use the Healing Wish set
In gen 7 OU Mega Scizor is really shitty. There a 4 new Tapus shitting up OU and Mega Scizor can only handle one of them to any degree of success, except it loses to Bulu's All Out Pummeling so you're better off just using Megagross for your Steel-type Mega. You can make the argument that Mega Scizor is worse than Standard Scizor (which generally only bothers to run Choice Band).
I wouldn't call any other Mega strictly worse. At worst they are usually sidegrades, or you can argue the opportunity cost might be high for pokemon like Mega Glalie
