The only real flaw that personal loot had prior to this change was the fact that you could potentially receive gear that you either already had or didn't need/want. But this issue has been alleviated by allowing players to freely trade whatever gear they've received amongst participating raid members. They can either choose to give an item away if they don't need it, or they can trade it with someone else for something that they do need. Essentially, everyone is their own 'master looter' as far as gear distribution goes. So in a way, the system hasn't even really changed. It's just shifted the power away from the raid leader and onto the individual player, solving the issue of ninja looting in the process.
There are also more groups now than ever, with everyone running for the chance at titanforged upgrades. So if the pre-patch is any indication of the future of pugging, then I doubt there will be any issues when it comes to group scarcity. The only groups that have disappeared from the group finder were the ones that were reserving all of the gear, which is a positive change as far as I'm concerned. I don't think the entitled special snowflakes are even half as important as they think they are.