Slutty_Felix said:
Well yes, but actually no. I think it was intended by sonic team to let him stay dead and that would certainly increase the sadness of that moment and would make Shadow's sacrifice a lot more valuable. However, they saw that everyone liked Shadow waaay too much so they decided to bring him back. I can't really tell if this is a good or a bad thing, but I love Shadow and it's always nice to see him in more games.
In a nutshell that's basically what happened and although a lot people hated his standalone game I'm of fan of it