I'm not sure...
The traditional LG paladin has its issues, but they can be both tedious and irritating or challenging and rewarding, depending on the player. I think the LG version of the paladin is the best starting point for the concept, just like the scholar is the best starting point for designing a wizard class, and the urban-savvy thief the best starting point for designing a rogue class, but I definitely don't like the game to tell me I should not try to stray away from the most common archetype...
In the case of a paladin, straying away in alignment can make it either easier to play or more challenging, again depending on the player. IMXP the player who ends up with a "lawful stupid" paladin should better have been allowed to play a NG or even CG paladin, because this would have avoided most problems when choosing law over good or viceversa; on the contrary, a player who is already good at interpreting the tension of these two "sides" of a LG paladin, can find new interesting challenges in a variant paladin.
But the flip of the coin about allowing too much freedom of alignment (or freedom of concept, for other classes) is that you may end up with a shortage of classic archetypes. Not a bad thing for a single group, but considering the whole D&D community, I would certainly like there to be creativity on character concepts but at the same time I also need to see some "kernel" of classic archetypes being the most common characters.
I'm mostly rambling here, I have no solution

But perhaps it would be good if the D&D designers would give different design weights to classic archetypes vs variants and oddballs, and then trust the gamers themselves to be able to come up with their own material for the not-so-classics. In case of the paladin, focus on the abilities of the LG version (I don't know, maybe make it so that 50% of the PHB material for paladin is mostly meant for the LG, and the remaining 50% for everybody else), but don't write "requirement: MUST BE LG! anything else illegal!", just explain that most or maybe nearly all paladins are supposed to be LG, vary at your own risk.