I mean... duh? The N64 had Ocarina of Time and Majora's Mask, Gamecube had Wind Waker and Twilight Princess, Wii had Twilight Princess and Skyward Sword. Breath of the Wild will be the first original Zelda game on the Wii U (not counting Hyrule Warriors), but even it had the remakes of Wind Waker and Twilight Princess. So it seems pretty obvious that there's a good chance there will be another main Zelda title on the Switch.

I'll probably buy it pretty early, but the real question is, how dependent on expansions will it be to reach the level of current Civ V?

"Sure, the relationship building is only half the battle, but it's the foundation on which your combat strategy rests; pair people up and you will deal extra damage, heal, and crunch through maps more efficiently, not to mention produce offspring with high stats and powerful attacks."

I'd just like to clear something up for anyone who might not be familiar with the series, or this game's mechanics: the relationship building is far less important to the core strategy gameplay than this sentence might make you think. You would be 100% fine just going with whatever options you happened to get for supporting your characters, without putting any particular effort into pairing up certain characters, even on the higher difficulties. Or you could honestly just ignore the relationship-building aspect entirely and probably be fine as well - though you'd be mildly crippling yourself by not at least going with whatever options you happened to coincidentally get.