I agree with Abp. Viganò, and for me, the following argument suffices to adhere to the rubrics of St. Pius X
1. A disciplinary law of the Church cannot be intrinsically evil, nor, at the time, can it be extrinsically evil.
2. Over time, a disciplinary law can become extrinsically harmful or difficult to observe, given a change in circuмstances. This is universally admitted by theologians.
3. In such scenarios, the law ceases to bind. This is the well-known principle of 'epikeia'. It does, however, require the absence of the lawmaker (which I admit; I adhere to the Thesis of Cassiciacuм).
4. There are numerous elements, Catholic in themselves, in the reformed Holy Week, which now take on a Modernist connotation owing to their inclusion in the New Mass with a Modernist intent, such as the use of vernacular, greater participation of the laity and more. Another example of a pre-Conciliar reform which takes on such a connotation is the dialogue Mass.
5. The principle architects of the Holy Week reforms — Bugnini and others — openly admit that the reforms were part of the whole, which whole ended with the New Mass. Paul VI even promulgated the New Mass as a continuation of the reforms.
6. Invoking the principle of epikeia, then, we should not observe the 1955 Holy Week reforms, for 'he who consents to the beginning consents to the end'. If our goal is the preservation and propagation of Catholic doctrine, discipline and worship, let us preserve that pristine Catholic liturgy untouched by the hand of Bugnini.