How about being able to bring in your other characters (AI controlled) for PvE events like strikes as an option. For those that prefer to solo, the added support and seeing your other characters in the same event would be really cool. Support characters can be really effective (like in Mass Effect). Being able to use your other characters would also encourage people to build out more. I know someone that only uses 1 character for everything. Having your own custom strike team would be incredible. The player could equip them however you wanted before the event starts. For example, being able to run a warlock primary with a defender titan and void hunter would be a powerful combination. I'd really like being able to see and interact with all my builds. It would be more like the original game trailers where we saw all 3 classes working together.