Great talk overall, a lot of interesting insights!
Changing the analogy to a fish in a tank suggests an assertion that these other intellectual modes are not important for human experience and wouldn't make communication more effective and efficient.
To tweak the analogy further: Otters are very good at swimming, but their habitats should include land.
Personally I don't think his usage of the term "[in]humane" to describe human media is appropriate. Who is responsible for this inhumanity? Our entire race is collectively treating itself inhumanely by not inventing entirely new forms of media and expression? That seems like a stretch. Are we inhumane to dogs because we haven't yet helped them discover their fullest and richest capabilities as a species, whatever those may be? I love Bret and his vision and talks, but I feel like this particular usage is heavy-handed shame rhetoric (I get that he is trying to light a fire under people, but it still seems forced).
some critical and important experiences and behaviors are excluded.
What defines experiences as critical and important, such that to exclude them would be inhumane? Is it inhumane that I haven't traveled on a spaceship to Mars? That seems like a pretty important experience. But of course that's ridiculous, because you can't include the infinite landscape of experiences that might be possible. Personally I don't think either analogy (dog or fish) is particularly apt, but I think the fish one is better because a) our generally known and accepted capabilities are not being forcibly restricted by another agent, and b) the stuff Bret is talking about is entirely new and not possible within our natural environment (i.e. there are many natural and accessible ways to write symbols on a surface, but nothing like that for arbitrary-dynamic-physical-hologram-things).
A) Our capabilities are being restricted by the circumstances we find ourselves in. A dog happens to be in a cage built hundreds of years ago. There must be some words to describe this situation, I think inhumane applies.
B) Now we can start opening the cage.
Edit: our natural environment is inhumane and awful. Your commentary seems to heavily favor the status quo in a way I can't relate to.
The additional inhumanity of media is from 2 things: the fact that information processing has been mostly limited, and that information processing has become really important lately, so a lot of people are spending a lot of their time in that limited environment.