LH is replacing its 2 class 340/600 on FRA to IAH by a 3 class 747 for the summer season. This could bring already bring down prices on the routes between Europe and IAH.
This could discourage BA to add even more capacity to IAH.
It's interesting they're doing this as IAH is not exactly the idea location for a vacation in mid-Summer....
I've always assumed BA runs this route for the connecting traffic in the front of the plane. On that basis I would have assumed the biggest threats come from EK non-stop IAH-DXB and SQ (no it wasn't a typo) starting non-stop IAH-DME.
I personally am heading to/from LON so I can't see me adding an extra couple of hours for an un-necessary stop in FRA.