User blog comment:Legionwrex/Why Destroy is the worst ending (besides refusal)./@comment-3228423-20120706122320/@comment-899316-20120706160213

Well, that all depends on a few things. Like who your Shepard is. If you play a power-hungry, Renegade, half-demonic jerk, chances are power will corrupt him/her. If you play a super-Paragon, defender-of-the-universe type, things may go differently. In the end, you just have to ask yourself whether or not your Shepard would stick to the galactic guardian thing, or go mad with power. There is, however, another factor.

When Shepard is turned into the new Catalyst, the shift is pretty massive. Shepard is no longer a short-lived mortal, and is in a position where they can truly look at the big picture. Their mental horizons have been expanded so greatly as to make them almost a different person from the N7 gunslinger they once were, as Shepbinger reminisces in the epilogue. It is entirely possible that mortal concerns like power are now beneath him/her.