The vents are a tricky one because there are so many competing objectives. In some circumstances good (e.g big) vents are great, while in other circumstances they don’t do much yet having bigger vents add weight and cost, plus can mean the doorway needs to be smaller. The X-Mid has larger vents than most competitors because I value that, but that does mean some extra weight and I don’t love having the vent strut, but without the vent is much less effective. So I am regularly thinking about the vents and mulling over how to do it better.
The 1P puts the vents above the doorways because that works the best for adding the poles via the vents with the downside of limiting how tall the door zipper can be. The 2P moves them to the end wall where they are a bit smaller and thus not quite as nice to insert the poles through, but you can just add the poles via the doorway and the end wall vent allows for a taller entranceway which some prefer. So there’s pros and cons to both arrangements and I’ve tried them both to see if there is a consensus on a preferred style, but I don’t really think there is.
Longer term I’d like to get the vents simpler (no strut nor velcro) while remaining functional. One possible approach is TarpTent’s newer vent style where the fly zipper has dual sliders and one opens up behind the vent. I like the simplicity of this but the second slider weight likely offsets the strut weight so it’s not lighter, and I’m concerned about how much venting it really does because you can’t open the zipper this far if it’s raining plus the stiffener brim of the vent is prone to being scrunched after being packed, so in real world rainy conditions I suspect you get not that much venting from a pretty small zipper opening behind a scrunched brim. Basically this style omits the strut but adds both a stiffener and second slider. Could be worthwhile if the stiffener was really good (not prone to bending/scrunching).

Regarding a possible buckle on the fly zipper, this is a tough one because I agree with you that sometimes it would be nice and that this tent is about being “reasonable light” instead of “stupid light” but at the same time all this stuff adds up quickly. If I make the two fly zippers a few inches taller (+0.25oz), add a second slider (+0.5oz) and add buckles (+0.4oz) the tent is over an ounce heavier than the current version just with a few simple tweaks. That would be >2oz heavier than a lighter setup with #3 zippers that some competitors use, and compared to the lightest possible option (door clips) this is 3-4oz heavier. 28 vs 29 vs 30oz doesn’t sound like much, but buyers are comparing 29oz X-Mid vs 27oz competitors then being 2oz heavier for 3-4oz does sway people. We’ve never had a zipper failure yet because the #5 zippers are pretty beefy, so it’s one of those changes that does make the tent better for harsh conditions but 95% of customers wouldn’t have value for it. More broadly, everyone has a bit of weight they’d like to add to the tent in an area they value (e.g. tougher floor, more space, stronger zips etc) and they’re all legitimate desires, but hard to satisfy because any individual change is minor but saying yes to many of the good requests would make it uncompetitively heavy. At least for the fly zipper buckle it’s something that users can add themselves relatively easily. I agree there is some stress here but don’t anticipate a large reduction in lifespan because other similarly sized tents (e.g. TarpTent StratoSpire) don’t use buckles and fly zipper issues are very rare.
One possibility that I have pondered is reducing the zipper from #5 to #3 but then adding the buckle. With the buckle taking strain off it might be just as strong or stronger than a #5, and would be lighter. The problem is that the sliders wear out faster on #3 zippers and a separating fly zipper would be a real bummer in a storm. Of course many companies use them (e.g. Locus Gear, Big Agnes etc) and the slider would be pretty easy to swap down the road if needed.
Right now the tent does have grosgrain loops on both sides of the door, so you can use cords attached to that to stake out the upwind door with those cords in an X to hold the base of the zipper shut as reassurance (while using the door on the lee side). It’s not as nice to use as a buckle but seems to help. Longer term, if I do start selling them myself down the road I could produce them without the buckle and then add buckles by request.
Regarding the small side of the door, yeah a toggle there is another “nice to have” feature that didn’t make the cut in the bid to keep the 1P sub 30oz. It would be nice to have. Right now you can clip the small side of the door to the grosgrain loop on the end wall (at the bottom below the peak). That’s not easy to do from inside, but it is a way to secure the side of the tent side open when camped in nice weather for that panoramic view.
I would like to do a solid inner. Hard to say if Drop will approve that. I regularly remind them that lots of people want it, so hopefully it can happen.
Sales of the tents are good. I’m sure the virus had a big impact on the 2P launch but Drop didn’t have that many anyways (1500) so they still sold out in 2 weeks and now are out of stock until the next batch in August. Considering there is often a long wait for the tents they are selling well, but would sell 2-3x better if they were in stock on a non-virus year.