After using both projects for awhile, I prefer the basic movement, and weapons system in Character Interaction, and of course the interaction component itself. For TPS Kit, I like the cover system, ladder and ledge climbing, special moves (i.e. rolling, sliding, vaulting) and the more advanced human AI system.
It seems like it would probably be easier to add the TPS Kit features to Character Interaction base project.
Personally, I would rather see TPS Kit expand on the features that are already best in class, such as the cover and climbing system, rather than add more features that other projects already do well. For example, it would be great to see the ladder and ledge climbing expanded to more versatile, and applicable to open world type games. Expanding those to allow for cliff and tree climbing would be fantastic. For the cover system, maybe it could be extended to work with foliage? Also, I see a lot of value in improving the versatility of the human AI to allow for different classes of AI to be either teammates with the player, or different factions of enemies, or neutral groups that become enemies under certain conditions.