My version of The End would have been highly spectacular:
*warning* Some spoilers below for the real episode*
The Titans know well in advance that the day of Prophecy is closing in.
They begin to recruit other Superheroes from around the world. (Justice League, ect.)
Slade returns, empowered by the power of darkness, with a massive, more menacing army of creatures straight from hell.
Even all the Superheroes together have difficulty against the massive army.
Raven decides to become the portal anyways, as it's her destiny. <---Same as the episode.
Trigon arrises, and now with full control, uses his Army of Darkness to begin turning the planet into a wasteland.
Even the Supervillians begin battling against Trigon's army.
The army is too powerful.
Slade appears and tells them that Raven is still alive.
All the Titans with Slade head to rescue Raven while the rest of the Superheroes keep battling.
How can the other Superheroes handle battling demon versions of themselves?
Raven is found, Slade has already parted ways in pursuit of his own interests.
The Titans try to rescue Raven, Raven is not a child, but she is herself, without her powers and moping around.
The Titans must escape and make it to the final battle with Trigon. In a surprising plot twist, Terra returns.
The door that Slade opened to regain his full flesh in blood is nothing more than a trap in my version. He must fight a demon version of himself, in which we learn shocking revelations about who he is, his past, ect.
The Superheroes defeat their demon versions the same way as the Titans did in the official episode.
The Titans join the other Superheroes in confronting Trigon, Raven still does not have her powers.
Slade defeats his demon self and regains his body.
Slade returns to join the final battle.
The rest of the plot is roughly the same as the official episode, Raven regains her powers, and kicks Trigons butt in what is a ten minute dramatic battle sequence.
Trigon is vanquished, the world is still in ruins and must be rebuilt, and Slade is missing.
The apocalypse is over, and our heroes live on to continue protecting the world from evil.
Somewhere along the lines, Robin confesses his love for Starfire. There is a disgustingly sappy make out scene to follow. A new TerraXBeast BoyXRaven love triangle is beginning, and will be the center subplot for the new season. Expect much angst and revelations of the inner workings of life to follow.