For cubemaps, you can use the nvassemble
command-line tool. Yeah, it's a bit more hassle, but once you make a batch it's pretty quick to run the next time. I haven't used it, but I bet the images are in the same order as the old plugin... +X, -X, +Y, -Y, +Z, -Z, ... which translates to the 3ds Max directions RT, LF, UP, DN, BK, FR.
Opening DDS, hmm, not sure about that one sorry, still using CS3 here. But... I think you can use the Texture Tools command line functions to spit out a TGA or PSD from DDS input? Edit.. yeah, nvdecompress.
Edit edit... talk to your tech artists!