Possible additional developments in no particular order

 - options to handle quantiles in rounded continuous data like SUDAAN does.

 - Score-based confidence intervals for glms

 - More general HT estimator for sampling without replacement
 	- using joint inclusion probabilities
	- using population first-order inclusion probabilities
	- using Overton's approximation and sample inclusion probabilities

 - Survival curve estimation (the standard errors are the only 
	non-trivial part of this)

 - Large data sets: see the surveyNG package

 - GEE. 

 - imputation

 - methods for multiple-response categorical data

 - Parametric survival models (you can do these with svymle)

 - linear mixed models?
