I'm a major sonic fan, and I wouldn't want Sonic to really die, but...
...It COULD work, if done properly...
something like this: After a long and arduous battle, Sonic sacrifices himself to save the world...and then after the credits, the following scene happens:
Something belonging to sonic (let's say...a bracelet or something) falls to the earth, and causes a cmall crater. A shadowy face (sleeping) jerks awake, and goes to look at it. After a moment, the figure puts it on, and you see who it is. A new hedgehog (one that actually looks cool, for once), that then dashes off at sonic speeds. Therefore, the main character dies, but the series continues. >_> oh. and needless to say, Sonic STAYS DEAD. If he comes back as a spirit to give the new hero advice, thats OK (at least it's an improvement over Omochao), but if he'd come back completely, then it would suck...
>_> that way, all the characters could age (I want tails to actually become cool again!) and then the series could sort of...be reborn.
>_>
<_<
/me dives into antiflame bunker to avoid incoming flames.