The only advice we can give to serious gvg players that want their arc goods to count: Don't advance past Future Era, or you will sacrifice your arc goods to do so.
This is very true and also shows yet another nail in the coffin of GvG. That if you want to be successful at the game you need to essentially stop playing the game.
At this point I think it would be better to just kill GvG off. I can see no way of them fixing the situation and I believe they realized this already. GvG has become a guild VS player and the game situation. The game wants you to progress, GvG is a big reason why one would not do so.
GvG is not available to mobile players leaving guilds to consider not allowing mobile players. With all the various maps GvG will never be what it was. Fewer and fewer players use it spread amongst more maps which turns a siege into a 3 hour ordeal of a handful of players and bugs. In order for a guild to be successful at GvG they must only admit players that play on browser, stopped all game progress at the determined era and be wiling to devote hours at a time to it.
All ages map seemed to me like a clear indication they have zero plans for GvG and are more than happy to let it die off. I don't think the die off is quick enough. With the small amount of players still participating there becomes a huge divide between them and everyone else. As a guild you have to decide if you want all your players games to be about the guild IE gvg, or if you'd rather have people playing the actual game they signed up for.
The first thing they need to fix is the ranking issue. A guild that does not or is comprised of mobile players cannot, compete with GvG guilds by no fault of their own. GE should count much much more than GvG because GE is available to all. GvG is like a festering corpse making everything else around it sick because inno doesn't want to be honest about it being dead and throw it out the door.
A 5th round of GE could takes it's place. It could be a sudden death round for players in the same world to go at each others to take the place of GvG.
As is, letting GvG slowly die is creating more and more problems between those that play and those that can't/don't. They need to just rip the bandaid off or come out and flatly say once they port to HTML5 GvG will not be coming with them. This limbo of two versions of the game, completely buggy and broken section of the game and platform and guild divisiveness isn't doing them any favors.