Single player is awesome, and I'm only on level 5. Such a satisfying obstacle course type platformer. The first boss was brilliant too, such a Mario Galaxy vibe.
The other big difference is Splatoon is a unique concept with a fresh perspective on shooters, and Destiny is... just another shooter, in a market saturated with shooters. If Splatoon had launched on other consoles it would have been criticised for lack of launch day content, absolutely, but it would still have been praised for its creative and fun gameplay. That's what gaming is supposed to be about, and that's why the majority of people love it. Sorry to hear you've gotten bored with it though.