If you are interested in working on any of these or have thoughts of your own, please subscribe to ​PostGIS developer list

PostGIS Raster

Raster Summer of Code Page

PostGIS Topology

#2074 ST_EstimatedExtent for topology

#2102 Ability to load topogeoms using shp2pgsql

#2144 totopoGeom have an extra arg to prevent addition of primitives to topology

PostGIS pgsql2shp dumper

#2045 pgsql2shp should not require temp table creation privs when dumping a query