How does Sanctum benefit from the Merge?
Dark answered this one pretty well.
Concerning players with the same name on the two servers, will it be like the past merges? (If so, could we get a refresher to how it goes again).
We will be looking into the specifics throughout the next weeks and will provide a solution and more information, when we can. Preferably all in one go.
Towards the other questions and concerns:
We are merging a Siwa into Sanctum. If the activity were high, we wouldn't be doing it. I wouldn't worry about a dominant population of any language, because it doesn't exist.
Merges are usually done to keep all the involved servers active. Personally, I've never understood the deal with other languages in any game I've played. Anybody can speak any language unless it is "foul language", right? I believe you benefit more from gaining activity than you may lose from not understanding the chat now and then. However, we don't expect a big impact.
I'd also like to reinorce that I also apply the same values in real life, too. We share a planet and universe. We just lose time filtering in countries and languages. We can benefit much more from one-another if we don't build artificial walls.
That being said. we are merging Siwa with Sanctum for various reasons. It is technically the most logical decision as they are already connected anyway - shared Client, Item Mall, TSE, Alchemy Table and tools.