This is unrealistic. The process from start to a fully finished character is huge, and if you didn’t start until the game shipped then you’d be bitching that there was too big a gap with no interesting updates after the game came out.
Also a lot of the people working on this content won’t be the same people working on the last remaining bugs. As you get closer to release, you have a smaller and smaller group of people fixing things otherwise it causes too much churn and you start introducing more bugs.
… and aren’t necessarily great for everyone. They cause a substantial number of people to feel nauseous.
If these achieve a similar effect without the downsides, then that’s both new and interesting.