Well for me lego island 2 clearly was just a soulless sequel cash grab.
It didn't have the same charm as lego island 1.
For example in Lego Island 2 the NPCs were just lifeless characters that either stand around, walk in a scripted fashion and they only talk when you press the space bar.
In Lego Island1 the NPCs had interesting things to say, they did interesting things.
The missions in LI1 were memorable. The mini-games also memorable.
The lego buildings most of them were unique.
Now graphics aren't important but it's kinda funny how the buildings, cars, trees, minifigures, etc have more detail in them than Lego Island 2. You would figure a newer game like LI2 would have better graphics.