So here's 2 ideas:
It's fun to code the robots the current way (scratch/game maker like) but it'd be amazing if there was the option to actually code a worker for those that find writing actual lines of code way more fun (yet needless to say, way more agonising) than using a 'drag and drop' like feature. It would probably help out with development of future functions for the workers as well, given the community could develop functions in advanced mode that could be pushed into the 'simple' mode either dynamically (the game uses created functions from advanced mode and will allow you to call the functions in the 'simple' mode) or through implementation (you guys implementing the functions directly but for the 'simple' version). That and if/switch statements are fun haha.
Going deeper would be supporting sharing functions between players, which should help the community grow more, through a menu in game/at the main menu. To give more incentive to players to try and get the second tier robot (or maybe even a new 3rd tier robot) the ability to access advanced mode should probably be restricted to later models of workers, that way when the player does upgrade their worker it'll actually feel really worth it - for some people.
When it comes to higher tier bots, I'd recommend you keep in mind that such bots should have something unique added to them each tier. By doing this upgrades wont just feel like an efficiency boost, like that feeling when you switch from using long roads of conveyor belts to using train tracks in factorio - there isn't much of a difference at first sight between the two but when you think about trains can 1. kill you and 2. wont drag you along unless you're in the train.
The games quite well built, especially for a pre-alpha, and is very promising at the moment. Keep up the good work!