Most likely Asana will be too simple for you then. For example, you can't assign more that two people on a task and estimates are just custom fields that are not so ingrained into the system, so you'll have troubles with reports.
> For example, you can't assign more that two people on a task
You can add as many people as you want at the project level but always assumed their philosophy was that that one person owns/completes individuals tasks/sub-tasks.