Eh, a game with the same title after 12 years is not that shocking. You can't top Worms in naming conventions. We had Worms in 1995, Worms 2 in 1997 and Worms Armageddon in 1999. So in 2007 we got a name called Worms, and in 2009 one called... Worms 2: Armageddon. Yeah.
But a soft reboot for Modern Warfare makes sense. Story got slightly convoluted and it's hard to add more to that. Start with a clean slate, so you can bring back dead characters and not demand people to remember 3 games' storylines and events.