We used to have a mobility talent tier where all three options were better than talented Cavalier is now. Our bad mobility seems to be by design. The issue isn’t lacking ideas to fix it (Long Arm of the Law and Pursuit of Justice were widely popular and worked great), it’s that they don’t want to fix it.
To some degree I get it: you’ve got a class that wears plate, has healing and group utility and an immunity shield, and (for Ret) is also supposed to deal competitive damage. We have to have some kind of weakness, and mobility is one of the only major options that doesn’t compromise the above “class fantasy” features.
And frankly, it isn’t really a new weakness. Ret paladins have been hard-countered by the W key for most of the game’s lifespan.