Smite and single classed sneak damage spikes are a problem with crits. The fact that they tried an alternative in one of the earlier packets suggests that they are aware of this problem, but how to fix it without making crits very boring?I don't get why this is still a thing. The current rules don't mention anything about critical hits, and the last one says we reverted to 2014 crit rules. There is nothing in the rules I can see that would prevent a paladin from criting with a smite
Monsters die fast enough without doubling all damage on a crit. One option might be to use inspiration to double all your damage dice, which would cut down on frequency of the big spikes. Another option would be only to double weapon damage but expand the definition of weapon damage to certain other class features. Another would be to add specific riders to class features rather than just doubling all dice. That could favour things like battlemasters, colossus slayer, one extra sneak damage die etc.
In my campaign, we do not allow extra damage from magic items to double on a crit.