If anything, they need to incentivize people to leave bera and take all their crap with them. Even out the populations a little bit, maybe reduce the bloat and lag that comes with it for bera.
That's a hard solution to implement. How do you incentivize people to willing put aside all of the progress that they've put into the world, and start over? Nexon has multiple mechanics in place that encourage people to play within a single world, the biggest one in mind being legion. Even doing something like offering players $100 in maple points to play on certain servers wouldn't work long term, and would be 100% abused somehow, which would result in restrictions being implemented. The only thing that comes to my mind is a world transfer event, but even that comes with it's own set of issues, as seen with the commonly mentioned Bera disaster.
I'm not an IT expert or anything, but I imagine that a server merge isn't that easy to implement either. If they just go ahead and do it right away because a lot of people would like a server merge ASAP, they may have to contend with serious issues such as missing characters. Then the Nexon GMS team gets a mouthful from the community saying that they're incompetent and can't do their job, like how it is right now. Maybe not from you, but many members of the Maplestory community seem to believe that Nexon GMS sits around doing nothing.
If Nexon GMS does have a server merge in the works, you should expect to wait several months or a year before it's done, and they wouldn't publicly announce it until probably a month before the server merge as well. Honestly, IMO Nexon GMS's best plan of action to avoid getting anymore backlash from the community is to simply do nothing, for now.