Chris,
Sure, I intend to deploy more updates for the older sets (frankly it's a bit hard for me to believe that the GP35, our second model, is almost two years old!) As our more recent models have grown in complexity (not to mention the push for creating new releases), so has it extended the amount of development time, but Nalle and I are gradually working to bring the older models up to speed.
Recently I've been doing some work on the GP35s and have been reworking the textures to high-res format. This DT&I unit is already out of date, but may give you some idea:
Also note that sometime this summer I plan to revise how we distribute the models -- in short, expect to see more railroad-centric sets instead of batches of individual locos. As with the Leased Loco Super Set, some sets may get new versions of older models before the previous releases.
Thanks,
--C.