And likely not what Roddenberry wanted. In addition from keeping ships from being able to cross the Galaxy too quickly, the redefined warp scale was probably supposed to keep warp factors from getting too cumbersome and out of control (i.e., Warp 47, Warp 106, Warp 5783, and so on).
Ironically, writers found another way to do that instead with fractional warp factors. But I believe that the Voyager
's declared Warp 9.975 was the highest spoken onscreen (not including transwarp and slipstream), and was more often than not simply called "maximum warp"...