Delta Vega wrote:
. . .Is there a definitive or canon explanation for this, as personally, I preferred the old dusky, gold shiny breasted Klingons, who always had a perfectly coiffured hairdo  . |
The TOS Klingons with the swarthy greasepaint and gold sashes looked fine on 1960s television screens but would have looked laughably cheesy on the big movie screen. (For example, their belt buckles were made of plastic bubble wrap.) So they got a major redesign for TMP.