Morris Fuller Benton (1872-1948) was an extremely influential typeface designer, having completed 221 typefaces.
He was a man well ahead of his contemporaries, and having carried on the work of his fathers work, is credited for the consolidation and design of the Century typeface family - let alone the conception of "type families" all together.
This contribution clearly altered the course of typography, giving typographers both pre and post digital age more freedom to create visual emphasis to letters or words.
As if this wasn't already a big enough contribution, M.F. Benton was then commissioned to modify the century typeface into the Century Schoolbook family, (commissioned by publishing company Ginn & Co) a typeface that was purely/scientifically designed for easy readability. He achieved this by utilising research by Clark University, which demonstrated young readers identified letterforms quicker through contrasting weight, but with the lighter strokes maintaining presence, as well as the importance of maintaining counter-form (negative space) around the letter which helped in recognising the face at smaller sizes.
In designing the typeface, Benton increased the x-height, stroke width and overall letterspacing, and soon this typeface became widely popular and familiar in North America, being the typeface that many first learned to read with.
Doyald Young, on the other hand, was a logotype designer / typographer who lived, worked and taught both pre and post digital age. Born in Holliday, Texas in 1926, he may seem like an unusual choice to use for this question - however Young's work was always unique and custom-made before it was digitalised, which - with reference to the Century typeface - demonstrates the immense advantage that contemporary technologies have had in the field of typography.
In an interview with Lynda.com - Young discusses his pride in a logo he made for "Prudential".
The initial request was to redesign the word prudential, so that it was friendly and closely related to a font but more tightly spaced and a little bit bolder than a normal typeface.
The companies emphasis on the word "friendly" lead Young to focus on the century typeface as its historical familiarity makes it comfortable which makes it friendly.
In short, Young redesigned a famous typeface to his liking. His improvements ranged from condensing the letter P and the tail of the letter a, as well as making letters, such as the letter t, taller so that they were more quickly read.
The result was Prudential Roman, an in between of ITC century book and bold - which in his words "satisfies the goal of many text faces where no 1 letter stands out. "
I believe that Young's work here shows how easily typefaces can be perfected and modified in the digital age - however one of the reasons that I love his work ( and his publications ) is that they both embrace technology yet prove that it doesn't necessarily mean there is more variation available. His work shows designers that even in this computer dominated age, they can still turn to their hands for inspiration and solution and transcend the limitations of fonts.