Hm... don't know what mods you using, but I don't have any of mentioned problems.
No CTDs at all, TC drops to x1 exactly when I need, boat dive, merchants missing with guns (well, at least not 100% accurate), u-boat hardly to spot for any ship (but not for airplanes
), convoys sometimes escorted with 1-2 DDs, sometimes unescorted, sometimes heavy escorted.
SH5 still have quite big amount of bugs and lack of some features, but not critical...
P.S.
http://www.subsim.com/radioroom/album.php?albumid=607