I thought of an analogy for our project that seems to fit fairly well. We're the "relational database for code". Relational databases change the way people think about storage. Before they existed, if you wanted to store some data, you opened a file and put whatever you wanted into it. When you read the data, you have to parse the file format, and you can only read the file sequentially, and so on and so forth. There are tons of different file formats that people use, but everybody does it differently, and if you wanted to be able to use the data in a lot of different ways, you had to think very hard about the different ways and design a file format that allows you to be efficient about it -- leading to greater complexity, bugs, and poor flexibility.
Enter the Relational Database. In order to use a relational database, you have to think a little about the data you intend to store. You have to organize it into relations: what pieces of data are associated with what other pieces of data, etc. You also have to tell the system a few other details about how the data will be used -- indexes, views, etc. But once you do this, it's massively easier to deal with all sorts of data. It's more flexible, because you can write queries that ask the database all sorts of questions that you couldn't have anticipated while you were creating it. Relational databases are also better performing, because the database creators were able to put in a lot of advanced technology to use indexes and perform query optimization and so on that you would rarely have the resources to be able to write yourself. Both this performance and this flexibility are gained from telling the database some critical information about the data that you're storing; you can't generalize the idea of a join between relations without the user telling you what is in a column.
We are aiming for a similar paradigm shift for software, especially communicating software: tell the system a little bit about how your functionality is structured -- what operations apply to which pieces of data. Stuff that you probably know anyway, or can figure out. Once you've explained this to the system, the system provides lots of flexibility (through making it easy to send messages, implement new objects, etc.) and performance (through parallelism, optimization, distribution, etc.).