Didnt hate the ending however it would of been much better if.
Shepard got inside the citadel via the "beam" once inside the room with Anderson he was met by Harbinger and TIM
Middle Choice
After a battle with harbinger he takes control of TIM, Once TIM/Harbinger is Defeated TIM has control over Harbinger Shepard shoots TIM in the head killing both him and Harbinger, The Crucible transmits a kill virus to all the Reapers and the galaxy continues eventually destroying its self thousands of years later via war
Renegade
After a battle with harbinger he takes control of TIM, Once TIM/Harbinger is Defeated TIM has control over Harbinger, Shepard helps TIM take control of Harbinger and use the Citadel/Crucible to broadcast his control to all reapers using them to solidify Humanity's position as the dominant spices of "The Last Cycle". Humanity using the reapers rule the Universe almost tyrannically for the foreseeable future
|Paragon (canon)
After a battle with harbinger he takes control of TIM, Once TIM/Harbinger is Defeated TIM has control over Harbinger Shepard helps TIM to control Harbinger and then broadcast a shutdown command across the galaxy using the Crucible/Citadel/Mass Relays.
TIM using all the knowledge he gained from controlling Harbinger helps humanity AND every other species prosper, aids and educates less intelligent races such as the Yagh into galactic communication/interaction.
Every ending then starts hopping to Major civilizations and characters from the universe showing how they continued after the war.
After the credits we see some alien race Far beyond our galaxy. The setting is a giant space construction yard orbiting some stellar phenomenon, cut to scientists from the alien race who report successful development of a Large scale Mass Relay that will allow them to reach our Galaxy. Then cut to a Alien General/king inside some throne room who reports "project:reaper was a failure, project:abyss is go".
Mass Effect universe stays viable, new threat is introduced but not expanded upon and we could still have after game DLC with shepard