I know my views and beliefs may ruffle some feathers in the traditional world, but they are simply my own. It is not my intention to attack any art or methodology of teaching. I am simply voicing my observations and experiences.
First off, I do believe that tai chi is a very valuable art for fighting. However, I have noticed that tai chi for fighting is rarely taught, and the furthest most schools go into application is in push hands or very low energy applications. That's fine, I have no problems with people only doing it for health reasons as it is an excellent way to satisfy those needs. I also don't mind those who exclusively play push hands, that's great, it's a great way to understand balance, force, and energy (in scientific terms, not mystical energy).
But here it is: Exclusive tai chi forms training will not make you a fighter. Being a push hands champion will not make you a fighter. Tai chi for health, will not make you a fighter....
What I personally believe is that for any tai chi practitioner who wants to learn the art for fighting, must first learn the basics of fighting. Yes, punches and kicks, fast punches and kicks. Then, not only will the practitioner have a better understanding of movements in combat applications, they will value the aspects of training and have more substance when moving slow. It really doesn't matter what style is done before hand, whether it is a kung fu style, kickboxing, karate, wrestling, or any other combat based art, but the basics of combat should be learned and understood. Only then can the student actually elevate their skills with tai chi training. Even the push hands experience will be more beneficial if they understand the fundamentals of fighting.
That will lead a lot of people to deny the fighter of their tai chi training and say that they only use their base fighting art in the ring. And it's true that they will throw exponentially more jabs than full tai chi techniques like Grasp Bird's Tail. However, the moment that there is an opening, the tai chi fighter can use a text book movement, and effectively if they train it properly. The rest of the fight will be punches and kicks, no matter how you label it, because punches and kicks are the fundamentals of combat. Tai chi for fighting is a secondary pursuit, like choosing a grad program after fulfilling undergrad requirements.
So don't expect to see slow movements in the ring to prove it is tai chi, or fancy hand positions after completing a technique unless the opponent is completely knocked out because posing wastes valuable ring time. Lastly, don't write off tai chi as a fighting art... as long as it is properly trained. And if you are looking to use tai chi more effectively, start with some combat basics. Go find a trainer, hit some mitts, work the heavy bag, drill fundamentals and yes spar. You don't have to go as far as sanctioned fighting but you should put in some good hours of sparring. And even when you do put your efforts into tai chi training to elevate your skill, you will need to occasionally spar to put your new lessons into practice. For instructors that want to teach the combative side of tai chi, make your students punch and kick things, pair them up and have them do mittwork or technique drills, have them spar regularly. Do your research too, not every technique application you were shown is the only way of doing it. Explore for yourself and see if you can apply the technique in a striking/standing grappling/wrestling/counter attacking context.
Good luck, and train smarter!