Tai Chi works like many other internal styles of martial arts (e.g. Aikido, Jujutsu, Baguazhang etc.) in that it relies more on principles of biomechanics for fighting rather than brute strength. Do not be deceived by the "flowery moves" into thinking that Tai Chi can't be an effective fighting form - for example there's one move in Chen Taiji where you grab your opponent's scrotum then proceed to "start the lawnmower" as you tear it off and simultaneously deliver a punch to the face.

But keep in mind:
1/ Not all styles of Tai Chi can be used for fighting. Some styles are purely for health. The main fighting forms of Tai Chi (also spelt "Taiji") are Chen, Wu and Yang. So if you want to learn more about fighting Tai Chi, I would recommend investigating those styles.
2/ Not everyone learns Tai Chi for self defence - even a lot of people who practice the fighting styles do so for health purposes.
3/ One weakness I see in a lot of Tai Chi training is that they start their exercises already in contact. For example one typical form of practice is an exercise called "push hands" and people usually start in contact before pushing against each other. The problem with this of course is that in a real fight, your attacker isn't going to be so compliant as to let you make contact with them first before you both start pushing against each other. It's better to practice what I call "sticking" (others may call it "searching") in order to locate your opponent's limbs and then you can commence pushing. The problem with the way a lot of people practice push hands is that they don't practice 'sticking' first. So the problem is - as you've pointed out before - overcompliant partners in training.

But this doesn't mean the techniques are flawed or the style is weak... it's a training issue.

Quote Originally Posted by Hot Rodimus
I have trained in Shito Ryu Karate,Wing Chun, Goju Karate in the past and had a great time doing so
I'm ignorant about Shitoryu, but I've tried a bit of Wing Chun and Goju. I like the way Wing Chun penetrates an opponent's defences and I like the tight defensive blocks of Goju.

Quote Originally Posted by Hot Rodimus
How long have you been training Gok?
A few years - but I very badly take massively long breaks between training which is slack and it's something I'm working on changing (long story - PM me if you really want to know more).

In terms of my competency, I'm by no means an advanced fighter. I would optimistically describe myself as being an 'intermediate' fighter - i.e. better than a novice, but definitely NOT an expert.