I think Jesus means exactly what He says. Just like I believe Paul means exactly what he says. So, for example, when Paul says we no longer serve (greek word means "obey" or "be subject to") the written Law, I believe he means what he says. I am not willing to redefine the word "serve" so that it means "be subject to the condemnation of".
So what does Jesus actually say in Matt 28:20?
teaching them to follow all that I commanded you; and behold, I am with you always, to the end of the age.
Did Jesus command people to obey the Law of Moses? I believe the answer is "no" - at many points, Jesus actually undermines the Law of Moses, not least the kosher food laws. Or when He violated the law to stone an adulterous woman.
What about Matt 5:18-19, ye may ask? Well, I have presented my argument in detail - please feel free to critique it.