Taken from Nachshoni on Devarim.

pp1183-1184
In this Book, Mishneh Torah, Moshe explains to the people about to enter Eretz Yisral most of the mitzvos which Israel will need. It mentions nothing of the laws of the kohanim, nor their actions, nor the ritual of purity and their deeds (because [Moshe] had already explained these to them)
For [the rest of the people of] Israel, [Moshe] repeats time and again the mitzvos that affect them, (sometimes adding an explanation, sometimes merely reiterating many of his warnings. Thus we see warnings against idolatory, for instance, with [Moshe] rebuking the people and instilling fear of punishment in them if they transgress these laws. A number of mitzvos are added here, such as yibum (levirate marriage) and the slandering of a bride, divorcing a women, witnesses conspiring, etc.

Ramban notes that there is also no reference to the sacrifices in the *Mishneh Torah.

N A number of questions arise from this statement. For these are the parts I struggle with, as they do not seem to be a part of our lives at present, yet we continue to hold them as sacred. Some say that in the time of the Messiah, we would have built a temple, with a High Priest,where we will carry out the ritual of sacrifice to HaShem again. The counter to that is that it is also said that in the time of the Messiah, we will have no need for the Torah, for it will have been fulfilled and we would no longer need it in its present form in the World To Come.

Q The question would actually be: What mitzvos written in the Mishneh do we not practice anymore?

Once that question was answered, I would then move to the next question, which is: Which of the mitzvos in the first four books of the Torah are practiced? Which of those practiced are not mentioned in the Mishneh?

This would produce the complete picture, something like this:

Torah	Mishneh	P/NP*	Comments
1	1	1	Righteous (Very Strong)
1	1	0	Why?
1	0	1	Fundamental (for spiritual & material evolution)
1	0	0	Why?
0	1	1	Foundational (for building a holy nation)
0	1	0	Why?
0	0	1	New practice (eg. barmitzvah)
0	0	0	Null (emptiness)

*P - practiced; NP - not practiced