I played a human mage and let Morrigan have the Well.
I didn't entirely trust Morrigan, but I figured that as the Inquisitor I should probably not bind myself to an unknown force.
I also thought she might be mad at me and leave, and I still could use her help.
I figured if she was willing to bind herself to an unknown force, than good luck with that (and later was like LOL, figures it would be AWFUL for her)
I thought if I gave it to her and she left, I'd just have to figure things out without it. I couldn't even be sure we needed it for anything in the first place.
I also thought if I gave it to her, she'd be more likely to stick around and actually help.
I did think *someone* should take it, though, because it seemed a shame to let that much Truth be lost forever.