In the recent "Painting the Stars" blog post, David talks about creating the art assets for an item called a fusion lamp. While not strictly terraforming, it acts as a miniature sun for a planet of your choice, presumably providing light and warmth to planets without sufficient sunlight. So it looks like there are plans to implement items that can compensate for negative planet traits. They may be rare finds like pristine nanoforges in 0.9.1 and thus unable to be reliably produced by the player, no further details have been shared at this point.
In other words, I would not expect terraforming projects that one can use to landscape the sector at will, but there will probably be limited ways to produce the effects you are seeking.