Wireless N is fast enough.
Good thing you are here to tell us how fast is enough.
What about people who work in places without wireless? And what if you work with large files a lot (Thunderbolt has you covered for devices near you, but now you have to wait for the network?)
Options, people!
A Gigabit thunderbolt/Ethernet adapter for $30 sounds like a good option if they really need to remove the built-in port (how much room does that same them?) Not everyone needs 1000 MBs Ethernet, but for those who do not having an option is a big deal!