If youre including bad Japanese to English translations I cite Final Fantasy 4, barely understood the plot thanks to it.

Grandia 2 has its low points ("Lollipop Lane kid, lollipop lane" and the ending where Elena says her Ryudo and Milenna are joined by the earth or some crap)

Odin Sphere over complicated its dialogue by splitting it into 6 separate scripts (plus alternate ending scripts). The makers kind of lost track of the story at times and it didn't mesh well.
As much as I love the first Grandia for other reasons, they had Justin randomly saying "Bogus" alot which kind of smacked of too much effort

The first Shadow Hearts game had a continuity issue saying Koudelka (aka Halley's mother) was dead when she wasn't. Also the whole pervy acupuncture guy was a bit erm.....pushing it.......a lot

On the whole I dont hate the writing in the RPGs ive played. Most i cite as having low points is all.