Definitely, the definition of "good" is subjective and one can never get it fully right automatically — but as far as TeX's line-breaking algorithm goes, avoidi

Definitely, the definition of "good" is subjective and one can never get it fully right automatically — but as far as TeX's line-breaking algorithm goes, avoiding successive lines starting or ending with the same word wouldn't require any major change, it could just be added similar to the existing method for consecutive lines being hyphenated (\doublehyphendemerits), without giving up the dynamic-programming algorithm.