My reflections on the issue of Sabbath keeping are as follows:
Much of the OT, including many of the laws (circumcision, dietary laws, sacrifices, etc.) were used as a tool to point Israel and the world to Jesus Christ. At least, this seems to be the very clear indicate from the NT writers, themselves. As such, there is no sense that NT authors believed that Christians were to continue to abide by these laws as a means of maintaining their new covenant with God. The laws pointed to the reality of the new covenant and were not elements of that covenant. (In fact, Acts 15 indicates that the ONLY requirements for joining this new, faith-based covenant relationship with God was avoiding sexual immorality, meat sacfiriced to idols and blood)
For instance, the purpose of the sacrifices were clearly to point us to the greater sacrifice Christ made. Thus, the commands about sacrifices in the OT are clearly not requirements for the new covenant as the sacrifice, once for all, was completed by Jesus. Likewise, dietary laws are clearly understood by early believers as symbols by which God separated clean from unclean and these images are clearly used by the NT authors to indicate that all things are clean (including pig-eating Gentiles) by faith in Christ. As God told Peter, "Do not call unclean what I have made clean!" Furthermore, the Temple itself was merely a type and shadow of the heavenly realities that really mattered...just as the Levitical priesthood was merely a weaker copy of the order of Melchizadek that Christ represented. In the same way, the observance of the Sabbath was clearly viewed by early Christians and the author of Hebrews as an image of the rest we now have in Christ. The rest from work that was part of the Israelite lifestyle (as were sacrifices, dietary practices, festivals, etc) were all a means in the old covenant to point to the reality of the new covenant that was far better and would eliminate the old. Christ is our sacrifice. Christ is our rest. Christ is what makes us truly clean. Christ is our ransom and Jubilee. He is our redeemer. He is our Passover Lamb. He is our circumcision which transforms the heart rather than focusing on the flesh.
All of these things...Sabbath, sacrifice, circumcision, dietary practices, Temple rituals, festivals, etc....point to Jesus. I think if we feel that God's pleasure is met in the keeping of these practices then we miss their true focus and the reality of them fulfilled in Christ. We have been set free from Law. We are not bound by trying to please God through diets, days and other such observances. The Apostle Paul was so emphatic about this point that he literally lost his life over this very issue!
In sum, I think we need to be VERY careful as we consider what pleases God. To believe we maintain a pleasing relationship with God by our adherence to these practices (and merely that Jesus empowers them to do them flawlessly) is to miss the actual purpose of these practices and diminish the work of the cross as an aid to keep the law rather than the fulfillment of it. We died to the law in Christ. We are free to live by grace. Do not be yoked with the burdens of diets, circumcision, other OT practices because you think that by them you will please God. God is pleased only in the perfect life of Jesus. By faith, not by our adherence to laws, we receive that righteousness and perfection.
Does this mean we should live lawless, evil lives? Of course not. We have been set free from the Law in order to live for God. But living for God does not mean counting steps on a Sabbath, offering sacrifices, or circumcise get our children. These things were signs to point us to Jesus and to continue in them, in my opinion, is to prefer the sign to the fulfillment of it...which is a terrible mistake.