Indeed, not really. Long ago there was XJJ2 which allowed server hosting/joining from a simple to use UI, including buggy co-op and race. Then Overlord released Project Controller which gave some desirable hosting setup features. But nothing that came even near what Plus allows us to do now.

About JJ2 being a financial failure, I somehow recall reading that it was a profitable game for both developers (Epic and Orange Games) yet a failure to both publishers (Project2 and GODGames). That's an entirely different thing, especially at that time on the market. Many small publishers that believed they could afford the 'risk' of publishing retail products from post-order software either became nonexistant (like Project2) or merged in with a larger company (like GODGames). Even now, nearly all game publishers are part of a large business structure rather than a squeezy little office space.

I do agree on the amount of bugs and the undeniably fast pace in which the developers moved on from the game. However, it's not uncommon for a playerbase of loyal fans to find as many workarounds and fixes as they can in order to make their favorite game survive. It's not unique to JJ2!

And I'd say the 'multiplayer unbalance' is somewhat judgmental, especially on weapons as it's easy to say Seekers and RF's are overpowered, yet it's usability depends on the map design and availability. And the mutliplayer gameplay that survived up to today mostly relies on user made content. The only official maps that kept people interested throughout the years are Battle1 (somewhat) and Capture3 (JJnet editied nowadays). Basically, any multiplayer game has spouted complaints about unbalance in some way or the other, it's all about the player's perspective here.

Many players that bought and loved the game in the past have indeed moved on. A few may seek their past interest on the internet and come across this website and Plus, but most just moved on and may never think about JJ2 ever again. For me, although I'm not an active online player, JJ2 still remains unsurpassed in quality by any other game in the genre. No other platform/action game I ever played has so much diversity and customization. I always tend to get reminded of the game and feel the urge to play it again.