Look at my screenshot http://heretics-hexens.ucoz.com/Screens ... 204657.png this is possible to use blending with out alpha test - true color png with smoothed alpha, when alpha has 2 colors than texture use alpha test edge, if texture has alpha with more used colors - no alpha test and we see awesome blending, like 3dfx era (more realist

So always assume that alpha has many colors or texture true color. Why not to try it, with test builds or just for test. or make in menu blend textures option (with warning use at your risk, incomplite, just for testing etc. so i had no glithes - i had awesome blending =)
try my wad http://heretics-hexens.ucoz.com/W_016.wad
gzdoom.exe -file W_016.wad -warp 11
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P.S. I am very sorry, but i am still hoping to see it.