Well I've heard this "unplayable" thing here a little too much, it certainly is playable as there are thousands and thousands who are playing it and playing the heck out of it. The online logs prove that, even if the tonnages are totally over the top.
Too bad Donitz didn't have SH5 captains working for him, the war would have been won by Germany in a month, and Britain wouldnt have a navy left, and the ocean would have an iron bottom.
Bugged and missing a bunch-o-stuff yes indeed, but unplayable? No.