It truly is disappointing Cover has become what it is now, I genuinely miss using it in SB, it was so versatile in it's usage, and I would like to see something done with Cover. I personally find it's range to be more than fine, as more often than not, no one should be so far spread apart that it's range becomes an issue, but of course randoms in DF aren't always so aware. But as of now, Intervention is just too strong compared to Cover to even consider spending 50 gauge on anything other than Intervention in a situation you could use Cover, outside of niche circumstances, none of which exist in 90 content presently that I am aware of.
As for Passage, I agree with your assessment that it wouldn't really make a difference in it's usage it adjust it's recast, it's somewhat particular in how it's used effectively, so you might get an extra use on a savage fight over current 120 second cooldown, but only if the fight lines up to allow it. Passage can be very fight dependent, in organised groups it use will be better used compared to a random DF/ PF group, but at no point will it ever be a mandatory ability, only due to the fact that it very optional due to no other tank having it. Simply because comps can comprise of no Paladin present, and fights are designed to be cleared with any comp, so at best it will always be a nice to have skill but nothing more.
As of right now though, I do agree with OP that Paladin does need a potency buff more than it needs anything else, preferably on Royal Authority and Atonement primarily, to allow 4 Atonement Fight or Flights to be a gain once more. This separated Paladin from the other tanks in GCD manipulation that made it fun to play, while the barrier in difficulty to execute has dropped a tad due to the extended stack duration, the Fight or Flight duration would be the only difficult part in it's execution. Any extra potency that may need be added should be given to the on hit potencies of the Blades combo. Overall, just tired of seeing people use the utility of the job as an excuse to have Paladin be bottom of the pack or deny any pleas for buffs.