I can kind of see your point that assassin is not a great class. But it does have its uses in a few builds. Assassin 8 is much better than shadowdancer 8
for example although shadowdancer 1 (7 extra levels to put in other classes) is better yet assuming you can fit in the dodge and mobility. And if you want sneak attack with a shadowdancer better have some rogue in too (or something).
That being said I stand by the statement "the point of assassin is not death paralysis". Refer to your first post for the reasons
You made it quite clear that death attack was poop on a stick and the only point is to see if someone will throw a 1. That is why it is not the main event of an assassin. An assassin HIPs then DA then rinse and repeat. Hopefully they have some other tricks.
Indeed assassin is not the power PVP class of say an RDD or SD for that matter but in NWN2 for going OC/MoTB you are allowed a lot more diversity. If you want to play an assassin or spirit shaman then go for it. You can do that.