Pretty much my thoughts exactly. Even if it doesn't suck, it still does away with everything that made the original so great, so why do they need to tie this new game into the existing franchise? If this was called anything but X-COM (or Xcom, or whatever. I haven't a fuck to give), I wouldn't be bothered. Just another generic shooter in an era of generic shooters. But this transplant just makes no sense.
In essence, a genre change doesn't have to be a big deal. Look at Fallout 3: Sure, you might prefer the older games, but what made Fallout so great was the setting and atmosphere, which were translated to the FPS version fairly well. The gameplay of the original Fallout games was ok, but it wasn't what the games were about. People don't play Fallout for the gameplay. Even though not every great element of the older games was perfectly preserved, a significant part that made them what they were was something that could be preserved across genres, which is why I'm perfectly ok with Fallout 3.
However, the same just isn't true for X-COM. Just as people don't play Fallout for the gameplay, people don't play X-COM for the setting or the story. "Aliens invade Earth and you need to fight them off" is pretty much as generic as it gets. The tense atmosphere that the game could take on is also something that a huge number of games strive to achieve in one way or another, and is certainly nothing you'd need to use the franchise for. The only thing that makes X-COM fans X-COM fans is the gameplay. Any significant change to the core gameplay means that X-COM isn't X-COM anymore.
X-COM Enforcer was an earlier attempt at an X-COM shooter, and it failed miserably. Why build on that legacy in stead of starting something fresh and new? Even if this new game turns out to be the best shooter in the history of videogames, it still won't be what the fans expect out of the franchise, and the name means absolutely nothing to non-fans. So why would they even want to use the franchise?