You make great points, and I appreciate your encouragement to go even lighter/simpler. If I were looking for a shelter for myself, or if my wife were in better hiking shape, I'd consider it. The SMD Haven looks awesome.
The TT Hogback is also really tempting as a larger, non-freestanding, lightweight shelter... space for four for twice the weight, but about the same price.
At this point, we're not covering the kind of distances that would make it worth the weight/comfort tradeoff. I'd say 8-10 miles/day is about it right now. And we often try to take along friends who are new to backpacking -- we love introducing people to the backcountry -- and new hikers often means heavier packs (we usually loan out our old gear), and that can mean even less miles.
And with less distance, comes less time spent on the trail, comes more time in the tent or around a fire. If we're adding that much tent time, the extra shelter and options are worth the weight.
If we eventually get to move out west, I'd suspect we'll start logging more miles on the trail, and then we'll spend less time at camp, and a more minimal shelter will make more sense.
As it is, hiking is not bad now with 10-15 pound packs (plus consumables). It's a huge improvement over the 25+ pound packs we were both using two years ago.
There's a sweet spot for everyone in terms of comfort/weight/price/convenience/safety/time, and I think that sweet spot evolves over time for most of us. For most of college/grad school, with zero money to work with, I was using a 6lb, 3man Wentzel tent that was $14 on clearance at Amazon, and a heavy, discontinued Camelback pack bought off of eBay. No sleeping pad, a rectangular 30* Slumberjack bag, and no cooking system -- hot food meant roast it on sticks over a fire. No fire, no hot food. And hiking friends were peers with boundless energy and no need for comforts, no worries about injury, no planning for emergency. Just grab whatever we had and hit the road.
Now, with a regular income, a wife, and less discretionary time, that sweet spot has shifted considerably. Now, it's about hiking together, and keeping us both happy. Someday, with kids, I imagine it will split into marathon ultralight solo trips balanced against shorter, comfort-driven trips with family.
So again, I appreciate the suggestions... if I find a great deal on a non-freestanding 2-person tent like an SMD Haven, I'll likely pick it up to see if it could meet our needs. No way to know for sure without trying it. But I'd be wary of making it our primary tent, or of paying full price for it... part of a shared budget and having camping as a shared hobby is keeping expenses "reasonable."