Hi Mariano
Yeah, that was probably the first thing i have ever looked at in regards to code completion because the beginning of this journey for me was figuring out the difference between regular and OCompletion (NEC, that used to be the default until a month and a half ago, & NOC, as they are called). The funny thing is, the code for OCompletion was actually still in Pharo until we removed it like a month ago, but using it was disabled by default. I don't think i've ever really used it myself but i understand the concerns :)
There was some brainstorming for it, but mostly last summer. This summer we focused on making the replacement for NEC work well, and so working on OCompletion got pushed back super far because we haven't thought there'd be so many things to fix. So i don't really have a good answer for you at the moment but hopefully will have something more to say sometime not too far in the future. We still want to work on it :) The thing to remember is that both NEC and NOC implementations were complex to the point of being horrible, so there's a chance if we just simplify NOC too and impose some limits for storing the results, as well as do proper caching, it might not be horrible after all. But it needs work.