I am unaware of anything in the ruleset that does not work, but there is a thread
here that is for the discussion of the ruleset which is still very much active. If you have any requests for functionality, have suggestions for improvement, or to get updates on when O.L.D. or N.O.W. might be released then that is where to find it/post it. I would put it to you that the system is in constant updates ( I think he has done 9 major updates to the system since its release with the 10th happening in the next week or so) and is thus certainly in full support. It should also be noted that your feedback is very important to us and we are heavily involved with our community so you will see more often than not questions on our discord, forums, or anywhere answered by our dev team directly (much like here which I must take a moment to thank Morrus for not only making a great system but always being present to answer questions and generally being involved, thank you, Sir). MadBeardMan (Colin who ported the system to FG) does manage also the Traveller 1 and 2 rulesets from Mongoose as well as a slew of other things ( I think he does a lot of Call of Cthulhu stuff) and the people that are invested in those rulesets are also important and therefore we must always do a balancing act as to what is currently the most needed focus of our energy.
That said, the WOIN system is flexible with tons of customizations and a lot of on the fly changes with dice pool manipulations and so on which is a great aspect of the game yet one that does not allow for a lot of preset automation within the FG ruleset. MadBeardMan has however done an amazing job bringing as much automation of WOIN core gameplay mechanics that is currently in the system and allowing other areas to be manually manipulated for better customization of bespoke elements.
I personally have just become invested in WOIN and like you all am very excited about the system in general and am starting a campaign in the weeks to come. I too want this system to find the popularity it deserves, I have no idea how popular it is but it should be even MORE popular

, and feel the best way to propagate that is to get involved and help those that push for the expansion of a great product.