I trained in Tang Soo Do Moo Duk Kwan for nearly 6 years, got my 1st degree in it.
TS, I assume you are talking about Moo Duk Kwan, since that is the predominant Tang Soo Do today. Following the end of the Japanese occupation of Korea in 1945, there were several martial arts academies that named their style "Tang Soo Do." The kanji for TSD is the same as karate; it's a generic term.
During the Japanese occupation (1909-1945), Korean culture was suppressed, including their martial arts. Instead, Japanese culture, including karate, judo, and kendo, was imposed on the Korean people. Thus, once Korea was liberated, most of the academies that sprung up were heavily influenced by karate. Also during that time, Korean martial arts were differentiated and labeled simply by school name. Chung Do Kwan (Kwan means school), Chang Moo Kwan, Moo Duk Kwan, Oh Do Kwan are a few examples (there were 9 big ones).
Moo Duk Kwan was founded by a man named Hwang Kee, who blended Northern Chuan Fa with Okinawan karate, and later on with his interpretations of the Moo Ye Dobo Dongji (Korea's oldest printed instructional on martial arts). Nearly all of the "Tang Soo Do" schools you see today stem from his lineage.
In the early 1950s, the Korean government decided it was time to revitalize the "Korean nationality" that was raped by Japanese occupation. A Korean general by the name of Choi Hong Hee proposed the idea of merging the many kwans under one banner, and thus Tae Kwon Do was born. This obviously created alot of internal conflict in the schools, since there were those that didn't want to unify, and those that did. Hwang Kee tried to keep TSD MDK separate, but even his school split down the middle, and that's why sometimes you see "Moo Duk Kwan Tae Kwon Do."
TSD MDK for the most part is far from TKD, and it is true that the former is closer to karate (technically Okinawan, not Shotokan), since they adhere to the same kata (Pinan, Tekki, Bassai, Kusanku, Jinto, etc). To be honest, it's hard to say which is less "pussified", at least in the US. They have both been plagued with McDojo and bullshido. There's so much variability in the two systems, but definitely you can say like any other "TMAs", they suffer the same weaknesses in general - more dead training, less resistance/pressure testing.