I haven’t used the new UI, so don’t assume this to be an endorsement of it, but even if you have good ideas about UI improvements and implement them, there still is pressure to make the UI look different because that, at a glance, shows users that they get something new.

And yes, “looking different” doesn’t have to mean “requires faster hardware”, but picking something that requires faster hardware makes it less likely that you will be accused of being a copy-cat of some other product’s UI.