That will force the 4K content to start catching on. Without companies adding 4K capable devices, 4K content won't ever grow.
Chicken and the Egg... Content distributors don't want to be bothered with making and distributing 4k content until there are enough devices using it to be worth while; and Device makers don't want to be bothered with 4k until there is enough content to make use of it. I would like to see the AppleTV make use of 4K for a few reasons.
1) The scenario above has to have someone do their part to get the other parties on board.
2) Regardless, 4K content will come, I'd rather have an AppleTV ready for it, than need to buy another device in a couple years. (Futureproofing)
3) Many new TV's already support 4K, maybe an AppleTV that supports 4K can help with better upscaling content.
4) If it had the processing power for 4K... maybe just maybe it has the processing power to handle other tasks when running in 1080p... like apps
5) I LIKE it when Apple leads the industry once in a while. Apple isn't often the first to a party, but they usually make a game changing entrance. but once in a while It's nice when they are the first there.
I'm sure there are other reasons, but those just rolled off the top of my head.
As for the remote... I'd Love for it to be BT and to have a headphone port like the Roku... those two features are great.