The Seedhouse isn't the only tent that has these shortcomings in the fast fly mode.
I have a SL3 which I bought to use in bug season which also goes with hot weather. Having a full mesh tent to protect from the bugs while being able to move around freely and get total ventilation from the heat is the benefit of this type of tent. Not the fast fly mode, IMHO.
I rig the fly, rolled up along the top pole with stakes already set, such that I can jump out of the tent should it rain, and have the fly deployed in 30 seconds.
Note that I live in Florida, bug season and hot weather are pretty much the conditions year round, so this is a perfect fit for the wife and me.
I also have a place in the White Mountains of New Hampshire (and will retire there if I live long enough). There, the SL3 is still a good bug season tent. But I love to camp in winter up there and I take my trusty Golite Hex3 which is lighter and the worry about snow loads is non-existent. My point is, each shelter has its place.
When it comes to the concept of fast fly mode on any tent, I have always thought; why not go with a tarp? It's lighter and serves the same function.