Well, as part of the UA/LH partnership in 1998 LH got to depart from the T1 gates. The T1 is pretty sold out and further gate space is not available. The US govt has little to do with this, its simply UA who owns the rights to the gates in T1.

The new western terminal coming up as part of the OMP by 2014 should improve things. OTOH LX is supposedly investing 1 mio $ to refurn the existing T5 lounge, so I doubt they are moving to T1 or the future western (T4) terminal.

I kind of like the T5. Its very quiet, the SK and future LX lounge decent (T1 has the crowded RCCs) and security OK if you know how to ask for access to the special lane.