The ability to use checkbox and radio inputs in the ticket body is awesome! Using custom CSS has even allowed for collapsible nested checklists (just which custom CSS was evaluated/supported in the mobile app).
It would be really nice though if we could have a secondary body field for checklists. This would allow this block to be fully collapsible or a separate side bar or tab. Long checklist can result in a lot of extra scrolling to get to the ticket replies.
Or maybe just move to a tabbed view for the body and replies which is common in other systems.