Answered by Sidi Mostafa Azzam
If one has many make-up prayers, in the Shafi”i school, is it O.K. to intentionally leave out the sunnahs in the prayers, and just perform the arkan?
If by “O.K.,” you mean permissible, yes it is permissible, i.e. not forbidden (haram). If you fulfill the conditions (shurut) and integrals (arkan) and avoid the invalidators (mubtilat), then your prayer is valid and you have acquired no sin. You can know what these are by studying my Immaculate Raiment: The Essentials of a Valid Prayer. Even if you never perform a sunna in your life, you are not sinful, as long as you fulfill the essentials (fara’id).
Even though it is permissible to omit the sunnas when performing missed prayers, the question remains, Is it superior? As we have learnt from Sheikh Amjad, the words of the fuqaha indicate that it is superior to fulfill the sunnas—not omit them—when performing missed prayers, even if they were missed without an excuse (see Nihayat al-Muhtaj, 1:381 (Dar Ihya’ al-Turath al-`Arabi)).
Even if it is superior to fulfill the sunnas, one must remember that there is urgency in making up missed prayers, for it is a huge debt that you owe Allah (how high is He!), and no one wants to stand before his mighty and majestic lord on Resurrection Day with such a debt. Considering this, I once asked one of my sheikhs the question, “What if someone leaves out some of the sunnas when making up missed prayers?” He answered, “Better than making them up on the tiles of Hell.”
The upshot is that it is superior to fulfill the sunnas when making up missed prayers, but at the same time, you must complete them before you die. So keep both these factors in mind and hurry up and complete them as soon as possible, and at the same do your best to make it a good prayer. I generally don’t advise omitting very short sunnas, since they don’t really slow you down. And Allah knows best.