I don’t know the reason for the Taco Bell change, but I do agree the brand refresh was appropriate. In my mind, they made some good decisions and some not so good decisions.
An organization's logo is a crucial part of its brand identification as well as an expression of what the company is all about. Great logos are the ones that we can immediately visualize even if we haven't seen them in awhile. The Nike Swoosh, NBC's Peacock, & Mercedes Benz symbol are just a few. Ideally, an organization should develop a fabulous logo and stick with it to achieve the maximum potential of being recognizable, but sometimes changes must be made. Maybe changing times and technology call for a logo's updating. Sometimes companies evolve beyond the image that their logos express. Other times it is a corporate merger or buyout that leads to a logo's alteration. No matter what leads to an organization changing its logo, the brand must make sure that it keeps the logo recognizable.