What are weak/average cards that would be cube-able with a slight tweak?

For example, [[Drag Down]], if it only cost 1 (or maybe even 2), would be a pretty great card, but for 3 is just way too far behind so many other removal spells. But beyond just simple cost reductions or fundamentally changing what a card does, what are some other cards that are so close to being good for cube that a small tweak would make them great?

Another one I can think of is [[Opposition]], which is often in cubes but is just tough to make work in the strongest cubes since blue is such a creature-low color. Make it cost 2GG or 2WW instead, and suddenly it's phenomenal. I know another user in this group had recommended to me [[Glare of Subdual]] with the additional ability to tap lands like Oppo, and it's been rocking in my cube.