Potentially refactor experiment structure to make more extensible

[ben-jones]

This issue may not require any code, but we need to consider if we can design the experiments in a better way to encourage extensiblity. They may be fine, in which case we should close the issue, but either way we should have discussion here.

[gsathya]

This issue may not require any code, but we need to consider if we can design the experiments in a better way to encourage extensiblity.

Good idea! I've been thinking about this for a while. The API looks solid to me. How do you think we can improve the Experiment's API? What are your thoughts?