The cataloging of a textual variations requires a decision on the primary text and variations are placed in the apparatus. Initially, the primary reading was taken from the majority of manuscripts. Over time questions on this approach arose. The majority text was biased to newer manuscripts and against older manuscripts which were fewer in number. Also there is the general belief that the older the manuscript, the more likely it is to reflect the original. I would summarize the current situation as replacing the majority system which operates without regard to quality with one that places the greatest emphasis on manuscripts which are perceived as higher quality.
Regardless of which system is used, the result is a primary and a secondary reading. For example, consider Matthew 27:35:
And when they had crucified him, they divided his garments among them by casting lots. (ESV)
Then they crucified Him, and divided His garments, casting lots, that it might be fulfilled which was spoken by the prophet: “They divided My garments among them, And for My clothing they cast lots.” (NKJV)
The ESV omits the prophetic element from Psalm 22:18 which the King James family includes. The quote itself is not wrong as it is included in John (19:24), but the ESV reflects a position the quote was not in the original Matthew and so follows Mark and Luke, in which it is also lacking.
One could also examine the issue taking a hermeneutic approach. On one hand Matthew's extensive use of the OT argues for inclusion; on the other, if excluded there are 14 "original" quotations.
1 Since Matthew makes specific reference (1:17) to the number 14 in the genealogy, it seems logical he would be purposeful to "follow up" with exactly 14 OT references. In this case hermeneutics affirms the decision to omit the OT reference as not original and suggests the reason why it was added to Matthew but not Mark or Luke.
Another example is in 1 Corinthians:
and when he had given thanks, he broke it, and said, “This is my body, which is for you. Do this in remembrance of me.” (11:24 ESV)
and when He had given thanks, He broke it and said, “Take, eat; this is My body which is broken for you; do this in remembrance of Me.” (NJKV)
"Broken" is included in the majority of manuscripts and in Orthodox traditions such as The Divine Liturgy of St. John Chrysostom. Arguably, the practice of reciting this text attests to its authenticity, despite its absence in manuscripts considered to be of a better quality.
What role should hermeneutics play in determining and/or validating decisions over which text best represents the original?
1. There are fourteen quotations introduced with almost identical formulas: 1:22-23; 2:5b-6; 2:15b; 2:17-18; 2:23b; 3:3; 4:14-16; 8:17; 12:17-21; 13:14-15; 13:35; 21:4-5; 26:56 [see 26:54]; 27:9-10. Dennis C. Duling, HarperCollins Study Bible, HarperCollinsPublishers, 1993, p. 1860.