You can discuss if an iPhone ever can be a camera for a Pro User. But i understand your point; recvideo app is not as versatile as FilmicPro. But, now the current reality is that Filmic Pro has no direct support for Tentacle. Yes, you can attach a SyncE to your iPhone and record the TC als LTC on an audio track using the right cables. I already hear you complaining. Or you don’t, and sync using audio with Plural Eyes or with the build in feature in Adobe Premiere. And there are downsides to that too. Its up to you which workflow suits you best.
It’s a shame… I’ve all around tentacle sync… so I have to move on to another app…
I doubt it since there is support for TimeCodeSystems incorporated. My guess is that they agreed to be the only one. Which is a bad choice imho.