Ryder is not a terrible character, he/she just not belongs here:

This is not something that needs to be proved. Its an axiom. There is even a hint in a "Shepard lives" scene that devs left as a tiny bridge in case they reconsider and decide to make another sequel or dlc that takes place after final battle, but alas that never happened. Andromeda is just a poor spinoff aimed to provide fanservice and appease as wide range of audience as possible, so no wonder it completely leaves off any reference to OT ending. 

I think it's kind of the point that Ryder doesn't belong where she is, in charge of a massive quest to resettle the milky way species in a new galaxy. She's not battle ready like Shepard was. Makes for an interesting game.

Looking at Andromdea - it doesn't. Also being green and out of place =/= acting like goofy idiot that is on his/her springbreak from high school.

Man my spring breaks were pretty boring. I didn't kill anyone at all. 

Speaking of killing - that alone is enough of a reason why Ryder does not make sense as a character, not to mention being a protagonist. Killing dozens of both aliens, robots and humans alike supposedly should bring one on the level of the seriousness of situation, no matter how green or young one is. So seeing Ryder mowing down dozen enemies with machine gun and few minutes later acting like 3rd grader while talking with scavengers looting fresh body is alone enough to make that character unredeemable and unwanted for next games. Clearly he either have some very serious mental disorder, or simply an idiot with IQ of a cork to properly understand what happens around him. Certainly such person can not be pathfinder and have thousands of lives depend on him/her, as well as does not provide an interesting player character one can relate to.

Excessive use of hyperboles does your "argument" no favors. I mean, really? Looting corpses is a thing to talk about now? It's a gorram time-honored tradition in RPG's. I refuse to live in a world where I can't loot what I kill. 

Wow! Op. That picture of Fem-Shep is absolutely awesome. You see that picture then look at the mashed up features of fem-Ryder and think...............Why, oh, why?

Unfortunately those few seconds of dialogue greatly illustrate Ryder character as a whole for the more or less entire game

When someone claims something like this proof is needed. That scene you mentioned was simply a bonus if you had high ems destroy even the devs said that scene was "fan service." That does not make it the cannon ending and you can get it with Femshep as well which kinda proves you wrong.

Since people are arguing over cannon that isn't cannon, I'm going to chime in

MY femshep is "cannon" regardless what bioware or other people say, she's the ultimate badass that doesn't have a boring voice :7 sorry, that's all bro shep is, can't go two hours without falling asleep with his voice. I also picked destroy as that was the sole purpose of my fight with the reapers and the rest made no sense and I didn't like the idea of forcing everyone to be part robot and part human and my Shepard would never control the reapers after seeing what they've done, they deserved to be obliterated to dust.