In my view, the major discovery of post-1957 ''syntactic theory'' is not 
''theoretical'', but methodological: That a huge amount of generalizations 
can best be found by adopting an ''experimental'' approach. In the 19th 
century and the first half of the 20th, syntacticians almost exclusively 
worked with corpora, and thus were limited to an ''observational'' 
approach. But just as morphological description requires elicitation to get 
complete paradigms (in many languages), so does syntactic description, to 
get the full richness of the ''syntactic paradigms'' (in all languages). 
 
(Let us hope that this lesson will not be forgotten, now that corpus-based 
approaches are becoming more prominent again, for good reasons having to do 
with technological innovations.) 
 
In addition to this methodological discovery, there were many claims about 
''theories'', ''principles'', ''architectures'', and so on, but these have 
always been largely speculative, and unlikely to stand the test of time. 
 
What remains of the published body of research is the empirical part. So 
all the papers that are neatly divided into a ''data/generalizations'' part 
and an ''analysis'' part have a good chance of continuting to be useful: 
Future linguists can read the first part and stop reading where the 
analysis begins. 
 
Martin Haspelmath 
 
(P.S. It's odd to say that ''modern syntax'' started with Saussure, as does 
Everett, because Saussure did not really work on syntax. I think it's 
fairer to say that it started with Delbrück's comparative Indo-European 
syntax, although this was pre-structuralist.)