I think people who would care enough to notice the differences between different Roku models are probably the same people who would take the time to look those differences up.
I could argue that the new naming scheme solves the problem of people not knowing which year's Roku model they are getting, at least for one year. The old naming system was pretty terrible about this. I mean there are multiple Rokus from different years with different hardware specs that are simply called Roku 2. The same goes for the Roku 3. You have to look up the model number or find a year listed to know which one you are buying.
I don't know how changing the naming scheme could make that more confusing than just releasing a new products called Roku 1, 2, 3, and 4 every couple years. Sure the numbers give you an easy way to tell which quality tier you are buying into but they do nothing to tell you whether it's the current model or not.