Making Prestige online-only really irks me as well. Chipper's reveal in 19 made me stop playing the game. I understand making it quicker for an online player to gain things that offline players can gain, but putting them out of reach for those offline players pushes them away. To those saying "it's free content, so I can't really complain", I'm glad someone bought the game for you, but I had to pay for mine, which means I'm paying for DD with my $60+ along with all the other content like Franchise and RTTS. Nothing is "free".
It seems like they're trying to push offline players to play online and this is the way they're trying to do it. However, what they don't realize is many offline players don't play online because they aren't as skilled and don't want to lose over and over trying to achieve a goal they'll never accomplish. I'm probably fairly average at the game and Chipper was an impossibility for me. Putting more content out of their reach puts them at an even larger disadvantage when they do try online modes. You aren't pushing those players into playing them more, you're pushing them away from your game.