Something Transformers has always lacked, since the 80/90s is bases and vehicles. Sure we get Titans, but the base nodes are usually OK at best.
What I think would be awesome is to start seeing large size bases/playsets, similar to the old micro master bases, or better yet, Autobot City, Iacon, Kaon, ect, or even brand new ones!
For the vehicles, they could do the ships from the movies, could do the pretender vehicles, could do the drop ships from The Fall/War video games, do the Ark/Nemesis, Cybertron ships, or new ones as well.
For every tier backed, they could add more. I think they should also be designed for full sized figures, because taking away the transformation steps, which Hasbro does pricing on, would decrease the price but allow for larger projects, even doing multiple pieces for a single set.
It would be so much more fun to have set pieces for transformers, especially if you could integrate the Titans such as Metroplex into them, similar to how he integrates into Autobot City/Iacon.