What makes WvW stale is you take a squad of 20-25 players out there to raid for 2 hours, and finding no good guild groups to fight. You end up either ending raid early or run around chasing cloud or banging your head into siege filled T3 keeps that are not possible to break. Due to the tiered system, this happens way too often. There are only a handful of servers that have enough guild groups to fight during NA. And they are all spread out in different tiers, giving you potentially weeks of boring matchup before you finally find one matchup with good NA content.
There are too many servers that have only offhour or odd hour content. There's nothing more frustrating than having people show up wanting to play GW2 WvW, but having no content to fight other than cloud or frustrating siege filled keeps. Or there is content, but they are on a queued map that you can't move your guild onto. So again, people log frustrated and slowly become uninterested in GW2.
The key to fixing WvW staleness is to simply give me content to fight, don't make me waste 2 hours looking for content. None of the ideas posted in the original post would solve this problem. Sure, change up the meta, tweak balance, etc.. are all no brainers that the devs should already be doing. But too often you could spend weeks stuck in boring matchups. This has to be fixed, server stacking only makes the issue worse as there are now less servers with competitive content to make raiding daily worth while.