Before I have ideas I need to talk to customers, explore their problems, and categorise their responses.
Having a way to capture those interviews in free-form, and then process the notes into problems to address, would be a great way to start exploration for a product in Aha.
I roughed out what this might look like here: https://medium.com/@danprisk/an-ideal-customer-development-tool-58240253a107
It's possible to already do this with plain text notes & post-its before filtering into Aha like this: http://customerdevlabs.com/2013/09/10/customer-development-notes-finished-post-its/
We recently rolled out a new feature under our Enterprise+ plan which can achieve this. This would allow you to capture information about customer interviews and link it directly to your existing product data in Aha! You can read more about it here:
http://blog.aha.io/new-custom-tables/
http://support.aha.io/hc/en-us/articles/209980386-Create-custom-tables
Note that this can also be achieved by using a combination of Product notes, features, reports and custom fields.
You can consider creating "features" for each interview (and can even rename it to be called Interviews). Personas and goals can be linked to each interview, and you can also create a wide variety of custom fields to support the use case.
There are a few related ideas and all of them seem to be marked as already exists and reference using Notes and custom tables (which is only available to Enterprise+). I also saw one suggestion to create a new product for each hypothesis and use features to document customer interviews. Customer development is really an important part of Product Management and I think it should be considered as a more defined feature that all Aha customers can use.
For storing more structured information than product notes can support, you should consider custom tables:
http://blog.aha.io/new-custom-tables/
http://support.aha.io/hc/en-us/articles/209980386-Create-custom-tables
Product Notes is very weak and definitely does not cover our needs. Please see also https://big.ideas.aha.io/ideas/APP-I-2857