What fonts containing multiple scripts have in common is that compromises have been made in the typography somewhere, compared to the type of each script if it was designed to work alone. A “Regular” style of Chinese is typically used at a different size than a Regular style of Latin, Arabic, or Thai. Arabic has a different basis for its alignments than other scripts. Stroke densities of glyphs across Unicode (i.e., how many parts each glyph has) vary from one stroke per glyph to fifty to sixty strokes, making variation of weight and width difficult and perilous over a broad range of scripts.
So a Latin type designer designing an ideal Latin typeface family who adds Chinese glyphs to the font family will very likely come to a different design conclusion, presenting different typography, than a Chinese designer designing ideal Chinese glyphs and adding Latin glyphs to the font family. This is not because of the type designers’ preferences, but because of the needs of their ideal readers versus the practicality of a single font for both. Supplying multiple versions of a multiscript font family is possible, but not always practical.