Yes, the zip is the weak point, on my Strosphere the zip length is covered by a waterproof flap. If I sewed an ordinary zip to the Hunker that would create I'm sure a long water leak area. I'm not intending to involve the hood at all, it's useful but it's not that useful in the rain. I relied on my tarp to keep my head and torso dry and to store my rucksack and boots, this worked well when I used it in the rain. I'm seeking advice from a lady that has a reputation of being skilled in zip matters. I've never bought a 'waterproof' zipped item before, do they actually work?
Another issue for me is that once inside, if I need to get out quickly, I find that a very difficult thing to do. I'm lying on the material and to get out I have to wiggle around, first raise my back, then push the material above and below me towards my bottom, then raise my bottom and continue to push the material down towards my legs. It's only then that I can get out. Having a zipped area would transform it for the better.