I have not seen too much of a problem with them in our campaigns. The changes to Trip in 3.5 do give it a bit of a boost but the boost applies to all tripping weapons.
Also let's see, spend a feat or have someone cast a first level spell (Enlarge) on the fighter instead
I would say the new Enlarge takes enough of the advantage away from the spiked chain to easily make up for any gain from the changes to Trip.
As far as stopping the "step 5' cast" maybe at low levels but by mid levels most casters I have seen easily make the cast-defensively check to avoid the whole problem.(Or if they are smart casters they are not even on the ground in the first place)
Also let's see, spend a feat or have someone cast a first level spell (Enlarge) on the fighter instead

As far as stopping the "step 5' cast" maybe at low levels but by mid levels most casters I have seen easily make the cast-defensively check to avoid the whole problem.(Or if they are smart casters they are not even on the ground in the first place)