TLDR;The real problem with bots isn't that they are too powerful, it's that they aren't as fun as they should be. The real problem with finding a solution, is that the problem wasn't ever properly defined. In the first section I go over what's really going on, and in the rest I go over my ideas on how to fix it. Feel free to skip to the idea sections if you just want to see what I have come up with, but please read the whole post before replying, thanks!
Defining the ProblemSo, I think most Factorio players can agree that bots have plenty of room for improvement, we just can't seem to agree on what that improvement looks like. I think a large part of the problem here, is that the real problem hasn't even been properly defined, so let's start there.
Now, there are 3 types of transportation in Factorio: belts, rails, and bots. The main issue that many people see is that for several reasons, belts, rails, and bots are way out of balance. They were designed in a way where they should work together and complement each other, but instead bot's basically take over once you get them. Unfortunately, due to how well bots scale, no amount of nerfing can really fix that... But, while this is definitely a problem, it isn't the problem... You see in other circumstances, this wouldn't be a huge problem, if something is a better fit for most situations, use it, no big deal. The balance may be a bit off, but it won't really get in the way of having fun. Unfortunately, the issue with bots is that there are far fewer solutions available to solve problems with once you get them. (Need more iron smelting? Place down a blueprint with a bunch of robotic smelters! Too many bots to charge? Add more roboports! Bot network to slow? Add more bots or research upgrades that affect all of them! Tired of adding bots by hand? Automate it so you never have to think about it again! And that's about it...) The bots have an absurdly small number of problems and solutions to those problems, and, since most of the fun of Factorio comes from solving problems, there isn't nearly as much fun to be had once you get them... And that becomes a huge problem, because they aren't the first method of transport you get, they are the last, and they overshadow everything else for most situations.
So, while the balance between belts, rails, and bots is definitely something that needs to be fixed, it's not what is really causing the end game to be less fun than early and mid game. The only way to really fix this issue, is to make bots as fun as belts and trains are, and the only way to do that is by making them require more strategy, planning, and problem solving. I really don't think that there is an easy fix for this issue, so I wouldn't expect to see a fix for this for quite some time...
So, with all that said, I have a few ideas that I think would add more complexity and problem solving to bots, in order to make them way more fun. I definitely think this would be considerably better, but, I still don't think it is QUITE there yet... So, I really want to hear ideas from y'all about how to make more problems to solve in a fun way, and then I can compile all of our ideas into a coherent, solid suggestion to be posted.
Idea #1: Roboport extensionsSimilar to Bob's modular roboports, but pretty different in actual implementation.
Instead of fixing roboport capacity issues by simply building more roboports in an area, have extensions to a roboport that you can build around a roboport. Each type of extension could have multiple levels, or for simplicity, you can just add modules to improve an extension... This adds additional solutions to problems, but also more problems to solve, as you can only fit so many extensions around a roboport.
- Antennas would increase the coverage area.
- Charging pads would increase the number of robots that can charge at the roboport.
- Bot Chests would increase the number of bots of a type can can be stored at a roboport.
Idea #2: Isolated RoboportsMake bots only work in the area of the roboport that they are stationed at, as if each roboport was it's own network. This allows you to have more control over how many bots of each type are in an area, as well as requiring more planning. Add a research to allow automating how many bots of each type are stationed at each roboport. Obviously by itself this would make bots nearly useless, however, that's where Idea #3 comes in.
Idea #3: Transporter BotsAdd a new class of bots that would transport items between roboports. This would allow optimizing speed vs quantity, as well as optimizing how items get moved over longer distances.
There would be 2 types of transporter bots:
- Transport bots: Small and very fast bots, but with a small stack size, designed for moving small quantities of items around the base as quickly as possible. (Great for supplying a field of assemblers.)
- Cargo bots: Large and very slow bots, but with a very large capacity of several stacks, designed for moving large quantities of a single item moderate distances very efficiently. (Great for supplying robotic smelting setups, or for chests that fill belts for production blocks.)