Some random thoughts.
Spirits are discounted nationally $50 to help make room for the redesigned 2018 line. But at the low end, compared to current ones, I think I'd wait until next year and get a new Spirit. Longer warranty (if I recall correctly?) and no cabinet to rust.
And I haven't read anything about why the new designs seem to have shorter lids, but to me that looks like it would provide a better overall cook as compared to having a taller lid, where the tops of food might not get as evenly cooked. Might be 100% irrelevant on my part.
The "default" Weber gas grill has always been some kind of 3-burner model, right? I suppose a 3-burner represents a good compromise on space and cost. That's $700 for a new Genesis today, and everyone who has ever bought one new, invested a similar amount on theirs, to keep the wheels turning at Weber. I suppose the 2018 Spirit version will be $500 or $600.
I briefly owned a Q300 and couldn't love it. For zoned cooking I want left/right or front/back divisions. Not inside/outside zones. For that reason alone, at $400 I'd buy a 2-burner Spirit any day of the week over a Q3xxx, which isn't even portable. I bought it for $60 and then spent a lot more on a new grate and other upgrades, not including new burners I probably should have purchased. I barely broke even selling it but it took a long time to get a buyer.
Ask the wife what sort of cooking she thinks she would see herself doing outside. Would she actually grill/roast on it, or use it like a stove with pots/pans?
What I want is for Weber to introduce an outdoor stove top. Forget the grill entirely. Make it "portable" or "for camping" if you must, Weber, but just give me a set of quality round burners for pots and pans. 2, (3 burners at the most) is enough. I can grill on my charcoal, thanks.