I don't really have a preference. On the one hand, i liked the addition of Jumpgate and underwater tunnels in Rollcage Stage 2, but i have to agree that i think the Outworld tracks felt better designed and more open in Rollcage 1. And the lack of Sapphire Springs & Neoto City in Stage 2 was sad times.
I guess there was pros and cons to both games though, really. Grip can combine the best elements of both games and improve it then some!