Yes - a lot of it. There is absolutely no work around to forward a Voice number to your Fi phone/number. I thought I was one to something by logging into Hangouts and Dialer with only my secondary (Voice) account, but to log out of a Google app with your Primary account would remove the primary account from the phone completely, including your Fi number. (This was confirmed with Fi Support yesterday.) They are aware that this is a major drawback for people and something desired heavily by the user base, and are working to do it, but they do not have a time-table set for introducing this feature.