My observation is most logos of successful companies nowadays take on classic or simple designs but with a twist. The look appears minimalist emphasizing more with the brand. The text uses simple font, not the artsy or complicated types, but they play on colors or patterns or backgrounds. Some examples are logos of most mobile devices or desktops, banks, bakeries or coffee shops, etc.
There will always be innovative logo designs that will become so popular closely identifying the brand or company and will withstand the test of time. Like the Nike Swoosh, the stripes in Adidas, Apple logo, Starbucks, McDonald's, etc. This task is difficult, challenging and requires careful understanding of the market and brand positioning. There is no hard and fast rule to follow, just try to be different.
Simple logos are easy to understand, visually attractive, and may last or be accepted longer in the market. Complicated logos with loud colors may be eye-catching at first but may tend to be an eyesore, boring or just a fad eventually.