Eh? Load of crap IMO.
Sure, he's only played one particularly good innings, but how often has he been needed? Once century and one fifty in three tests is perfectly good, especially given that he's also been keeping very well (today aside). If Geraint had made one century and one fifty in the first three tests England fans and pundits would be over the moon with him. England would probably have done a fair bit better in the series, too.
If he fails in the final two tests the comments about his "one good innings" might have some merit, but one great innings and one handy one in three tests for a keeper is completely acceptable. Incidentally, his batting average in the series so far is better than Hayden, Langer and Symonds, not to mention every England player aside from Pietersen and Collingwood.
I know a place where a royal flush
Can never beat a pair