I don't have a good understanding of the storage and handling aspect, other than to say I think most of the leakage is from embrittlement, for which the primary defense is ceramic coatings, or periodically baking the pressure vessel. That is to say it seems like a manageable problem. Design limitations are also manageable IMO. Ok it's unfortunate it can't be made into any shape like batteries but it's also not significantly worse than a fuel tank.

For distribution, of course there's no network if no one is driving hydrogen cars. It's not that much of a leap to imagine that gas stations will start selling hydrogen surely.

Regenerative braking is possible for HEVs. The Toyota Mirai has it.

I don't really follow you with industry synergy. Like people are using batteries so batteries are best? What if we hit peak Lithium (or China puts the squeeze on)? In that case it would be better to have an alternative up your sleeve.

the transition picture with hydrogen is a lot lot worse than EVs.

That may be your opinion but I'm not convinced. Japan and Australia are going all in on Hydrogen. I don't know much about this, but it seems like there's plenty of smart people who believe it's viable enough to invest entire countries economic futures on.