How about a DLC let you build Robots by your own? Maybe even build synth if you choose Insititute path? It can also make robot perk more useful. I seldom see people mention this.

I know there are a few mods can do this, but it would be greater if Beth can officially put it in the game.

That perk is far too situational and its picture is too misleading. I could see Bethesda allowing us to craft our own robots and modify them similar to weapon mods. Similar to http://www.carls-sims-3-guide.com/intothefuture/plumbots.php from the Into the Future DLC for Sims 3. Fallout 4 has already taken its first step in becoming The Sims: The Post-apocalyptic Edition with Settlements so it could stand a few more Sims ideas.

Although, DLC almost always means $. Personally, I rather have it as a feature introduced in a major patch rather than part of a DLC.

Here is what I think: 1. Beth should put some basic robots-building mechanism into the game as feature by patches, make the robot perks more useful and practical, maybe we can even upgrade Codsworth. 2. Let players control or adjust Synth production if join the Institute, because right now if we join the Institute and become the director, it seems we don't have any power to direct the production of Synth, except contantly taking radiant quests.

Other than these, if people want more, like a whole joinable faction build by robots such as the one in USS constitution, then they can make a DLC.