You should definitely give it another try. I felt exactly the same at first - aesthetically it was just so disappointing coming from SSX3, and the Deadly Descents were a terrible gimmick (I didn't enjoy any of them).
But underneath it all, it's still SSX. It still controls fantastically like you'd expect it to, and once you complete the campaign you can play free ride on the good maps or do Global Events - which are like continuous multi-player events to set high scores, and I found that really engrossing.
For real? After trying the demo I agree with this metacritic reviewer, which is complete opposite of your opinion:
This ruined every good memory of the series I ever had. Instead of a fun, wide open adrenaline rush to share with friends, you'll spend all your time either speeding out of control into unseen bottomless pits, or flying backwards up the walls. The entire environment is there to trap you, turn you over, or disappear you into oblivion. I would say thank goodness for the reverse feature, but since the rest of the game continues without you it's just a matter of giving up yet MORE time to the turns-on-a-dime AI. Speaking of turning, the control is similar to racing down a hill in a red wagon, with the handle BEHIND you. You'll be all over the place. You need speed, speed, speed to win, but using any will quickly fly you into a dark crevasse, or up a snow column leaving you facing the wrong way with no means to turn around.
I strongly regret that there are no game return policies because I hate. Hate. HATE this game. After I bought and loved the last 3 installments.