I would like to see more well-integrated systems of gear. Put together a set of stuff that is designed from the outset to work well together, to make it simple for people newly interested in UL/SUL to get started.
I think for many people, the most overwhelming part of the UL experience is the learning curve needed to pull a pack together, and the dozens of pieces of specialized gear it seems like you need to get from lots of different vendors, all cottage, all with the extra costs, shipping fees, etc, that go with that. Even if some of that means that you source (or get shipping/shopping agreements with) from other cottage gear manufacturers. I'd love a one-stop shopping to get a checklist of recommended gear that I know will work well together. I think the REI-crowd proves that there are a lot of people who have money to spend on hiking/camping and would spend that money going UL/SUL if it were easier to get started.
Also, a super-poncho-tarp would be high on my list. None of the existing poncho tarps I know of are larger than ~5'x9', which is pretty intimidating for a new tarp camper -- If you could develop a poncho tarp that intelligently folded/snapped the extra fabric, but spread out to be ~8'x10', you'd have a tarp that even a beginner could use in the field, and would ease the transition to SUL gear. It doesn't even have to be a rectangle. There's a video somewhere on youtube of the Equinox guy setting up an 8x10 tarp with four stakes and a single trekking pole, but it involves essentially wasting the corners. It might be possible to look at non-rectangular tarp formats that would work better as a poncho, but would also allow large protected areas for beginning tarp campers.
Another option would be to develop two poncho tarps that snap/zip/velcro together so that two people hiking together could easily use a pair of poncho tarps to create one larger shelter. Two 5x9 poncho tarps that suddenly became a 10x9 tarp would solve the problem with a lot of elegance and save a lot of weight, while still providing maximum protection.
I'd also like to see cheap ground cloths with bathtub-style edges. Sure, it's easy to do this yourself as a modification, but should also be really easy to do for people... 1" of bathtub around a groundsheet would make it far less likely for water to run or pool into your sleeping area, especially with the larger tarp above.
I want ultra-cheap SUL packs. All of us have reusable grocery bags we paid $0.99 for or got for free. Ikea sells giant blue bags for $0.69 that are lightweight and strong. Both of these types of bags are designed for repeat hauling of fairly heavy loads of groceries (certainly loads comparable/exceeding what we put in SUL packs), and these bags weigh only a few ounces. I can't see why someone hasn't created a reusable SUL pack using similar materials. Make it super simple, similar to the Zpacks Zero packs -- one large main body and shoulder straps. I can't see any reason why these couldn't be mass produced and sold for $5. Sure, they wont last for years of abuse, but for hikers that are just starting to go UL, this gets them there for $100 less than the cheapest other alternatives. If they like it, they can always spend more later, and get the same thing made out of cuben.
Sure, it's not going to last for years, but it would give people an easy inroad into ultralite hiking, and I'd bet the $5 version that is just a big pocket with shoulder straps could be sold to supermarkets and other stores, especially in urban settings.
Sell a $20 deluxe version that has all additional features: Simple side pockets, a large mesh pocket on the back for drying gear or for overflow gear. Wide straps with light foam in them and a very simple waist belt and sternum strap... A lot of true SULs who are careful with their gear would get one of these and use it for a long time.
There is no reason simple packs need to be $100+. Nothing exists in the $5 backpack category, and I just don't understand why, when grocery bags for less than a dollar have basically the same function and materials -- just need a little different configuration.
Anyway, lots more ideas, but those are at the top of my wish list.