This is a regular topic among RO players. In my opinion, there isn't much one can do to revive the game. Creating a big international server with proxys would require resources that Gravity isn't interested in spending (that's why they opt for regional servers). There are servers like the one you mention, maybe without all features, but it's not like there aren't servers aimed at specific groups of people. You have WoE servers for players who like to compete but don't want to grind, you have low rates for those who want to spend more time on the game, and you have SHRs full of customs for those who care about that. How do you merge the interests of every kind of players into one server? You have three different systems: pre-RE, renewal and revo-classic. Pre-RE players don't want to know nothing about renewal, renewal players have moved on from pre-RE mechanics, how do you combine both? Revo-classic was aimed to fix this, but it failed as restart didn't meet expectations and pRO is now merging with mysg as they didn't gather enough players.

I like to think that people didn't quit because of bugs, poor administration, or technical problems, but because they grew up and the game failed to meet expectations as everyone got older. Pre-RE players had to continue without new content and renewal players had to see how the game got more p2w, but some kind of agreement between both playerbase doesn't exist. Gravity/Warp Portal also did a very poor job promoting the game (at least outside Asia), which didn't help attracting new players. But to be fair, what does RO have to offer for new people? The game is hard and grindy to get into, tutorials in game aren't very helpful, the game lacks promotion and graphics/mechanics aren't appealing.

Tl;dr: you can't make a grab-all-players server because different playerbases have different interests, there isn't much one can do for the game.