While I don't understand everything said in this thread I think I got the most important, while I don't really need more than the 32MB right now (I am still playing with the board) having a way to extends it which does not involves recompiling the kernel or bootloader (that really sounds scary) would be really nice. The non contiguous part may be annoying but I think multiple cells of 32MB could still be useful if this can't be asbtracted.
For now I just reached the point where I have a program of my own running on the parallella and epiphany cores, I still have to figure out why the epiphany part is so slow (I need to look at the math optimization flags I think) and why the communications between the cores and the host is not entirely working as intended.
So as you see I still have some work/learning to do before I can really decide whether or not the 32MB are enough for me