Signs with romanized Japanese words might not convey any meaning, but it's sometimes useful for people who don't read kanji to see the pronunciation of the Japanese words. Sometimes you find yourself "collaboratively navigating" with a Japanese person and you're better off saying "I can see a sign up ahead that says Monbusho" than saying "I see the sign to the Ministry of Education".

For that reason, I think it's probably a good thing that they are keeping "Dori" in signs like "Waseda Dori Ave.". Although I dislike the tautology, I think it provides non-Japanese speakers with the words they need to be easily understood by Japanese people that they might speak to. If a foreigner just says "Waseda Avenue" to a taxi driver, the driver might think his passenger wants to go to Waseda University ... Not a big problem in that particular case, but I'm sure you can think of other examples.