We're working on a simple way to do deal->email association. Right now you can only do deal->company->email, so if you have concurrent deals on a company there's not a great way to disentangle them.
You got thoughts on how you'd want that to work?
Big companies have different departments. You could have a deal with department X at TargetCo and department Y. Generally those are different people (and emails) at each of those departments. So you associate email to the deal based on what email it's copied to.
Just use emails to link to deals. Forget about company.
Company association is useful. But it needs to be a historical association. Example Jonny works at MSFT now. But used to work at FB. Jonny could help you win a deal with FB even if he doesn't work there now.