Anotherthing;
With a FIS you knew exactly what it meant - Flight Information Service - a service giving information pertinent to the safe and efficient conduct of your flight etc etc.
How do you know exactly what it meant from that description? Does it include traffic information?, can you use radar? What else does it include?
Information pertinent to the safe and efficient conduct of your flight - what's that? The price of fuel at destination and alternate would help with efficiency but that's not included.
The fact is, lots of people
thought they knew what FIS was, but didn't. So the services needed to be re-defined. Changing the names helped stimulate the education.
If you still think FIS is a nice clear service level - go and read the ICAO description of Flight Information Service in section 9 of PANS-ATM. That's Doc 44444 if you want a reference.
VL