We're not yet entirely sure what shared-world means tbh. They've been talking about reducing the number of players you see in a playfield, so that you'll be less likely to run across people whilst in Kingsmouth (for example), but still see other players in London and Agartha. They've also suggested that all the game content will be doable solo, or in groups. So I guess there will either be dungeons where you have NPC support, or scaling difficulties based on player numbers.
That could also explain why nightmare dungeons are not going to be available at launch, to give them a bit more time to check how that system works out, and how it all scales up into NMs.
They've said that cabals will still be around, and there will be big multi player events like the golems, but they're being moved to Agartha (bit like Hatekeeper was) instead of being out in the player zones.
ODO will continue to provide as much support as we can - till the open beta drops or we get more info though, it's hard to say just how much that will be. They've said for example that they want to make chat less obvious, so it'll be on autofade.
The sad truth is that TSW as we know it is going into maintenance mode. As far as I can see, it's no longer possible to buy TSW, so there are no new players coming in. All new development will be for SWL, so whilst the servers will remain on, the numbers of players is going to slowly decay until there's only a few die hards left. ODO is not going to close in TSW, and we will try to remain as wonderful as we always are for as long as we have active members.
This is a purely personal opinion, but I would expect the population of TSW to crash as soon as SWL becomes widely available - be that open beta or launch.
I think there is scope for SWL to be a great game. We all know TSW's story is fantastic, and if they've managed to improve combat, client optimisation and the look of the characters, then it should be able to build on that foundation. The reticule combat system reminds me of tera and wildstar, both of which have good combat for most players. I do worry that it's going to create another game where lag is a game killer though, which would impact the world wide single server idea. Honestly, till we see what they've done though, it's just scaremongering, so I'll try to leave that alone!