What is this discussion even? Wyll is only destined for an evil ending if you play as him and lead his character there. The game provides a wide plethora of interesring situations and meaningful dialogue options, a lot of which can be interpreted as plot turning points for any desired transition. If you fail to develop a character properly in order to be satisfied with the given state of affairs in the end, thats on you... we are talking a role-playing game here, not a scripted dialogue simulator where every story bit and decision is interpreted for you, in great detail. You need to do some RP between the lines to make the things feel right and organic. If you do some actual role play you'll never get into a situation when a goody-to-shoes suddenly enslaved the world or any other absurd situation.
You can roleplay your chara any way you want of course, but in this case they decided to create origin specific endings that they seem to think fit the characters best. There are no other alternatives other than the generic Tav options. There are no options to be a pragmatist using the power for the greater good, which is something one could expect from Wyll in particular. That's how I'd play his origin after seeing how he behaves as a companion.
