Rather than discussing the pros and cons of UTC and leap seconds, just create your own time system.
You could call it OpenTime. OpenTime will use NTP servers where the Stratum 1 servers are synced to some time standard that doesn't care about leap seconds. That way the consumer can chose to connect his machines to UTC or OpenTime.
And what do you do if "OpenTime" and "UTC" differs so that it matters? Do the fligt leave at 1200 UTC or 1200 OpenTime? Most countries have a law that says something like "measurement is to be traceable to a national standard" for legal and trade use. (weight, mass, volume, current, time ...). For those who don't knew, none of the national labs that have local representation of UTC have the EXACT same time. So if there is a dispute you need to be able to show traceability to YOUR national lab. -P