I've been wondering if I'm getting the best video quality or even the correct quality stream on my iPad Mini 4.
It seems quite blurry even though the pictures it takes are sharp so doesn't help in knowing if you are in focus or not.
I've also noticed going from video to picture mode appears to decrease the stream quality although the settings are the same (iso, cinelike etc...)

Anybody else seen this?

I had the same issue with another tablet, Asus Transformer Prime (TF700).  It turns out my 4 year old, Quad Core, 10 inch tablet couldn't decode the video stream. So I ended up switching back to my LG phone.

However, I do recommend you try switching the video to 720p or Up to 1080p to see if it changes anything since I believe your tablet is more than capable of decoding the video.

Also, try focusing or refocusing..just to be certain it's not a matter of focus. Try this with the drone being stationary... to determine if it's focus or video issues.  - Just a thought!

I turned the video stream up to HD but doesn't really change anything.

I've noticed the stream rate about halves when going from video to photo modes with the quality noticeable degrading. 5.8mb/s to 2.5mb/s. Any body else seeing this?

There's a toggle for Hardware Decoding in General Settings, I would expect this to help on devices that support it, might try giving it a play. You could also enable Focus Peaking to give you some comfort that what you  want to be in focus actually is, even if it looks blurry on the iPad. Good luck.