I had this in the viability thread, but here is some speculation, more on routes than anything:

-elimination of many of the summer seasonal / leisure routes, along with routes that do not carry enough demand. I would think the logical thing would be for UA to route lots of traffic through *A hubs (FRA, ZRH, BRU) to drive coverage to Europe and cut direct flights
-possibly rethink utilizing NRT as a *A hub for Asia flying - maybe reinstate connections from IAD and ORD, since there are no slot restrictions. Perhaps limit direct flights to China solely to SFO and align NRT-PVG/PEK/HKG on NH to work for connections elsewhere
-heavy frequency reduction of premium TCON routes, retiring sUA 752s (and possibly some sCO 752s), and densifying the routes using a mix of 788s, 78Js and HD 772s
-early retirement of older widebodies? Perhaps the 764s are first to go, before any capex is sunk into retrofits?