Cap'n Kobold
Hero
It is just as skilled (prof bonus) with either. However a dagger has properties that a less-athletic and powerful Tabaxi can take advantage of compared to its claws.That makes sense to me but is why it would seem like a tabaxi would be better (or at least equally as good) at using its claws compared to a dagger.
I think that you're simply taking a different view than they did.I really don't see how finesse claws unbalance* - for flavor it just seems weird that a warlock tabaxi would use a dagger/daggers when it has natural weapons that it would be just as proficient with (and has been using longer).
* Compare this to Lizardfolk bite which does a higher dice damage or Minotaur horns doing 1d10 with a +2 racial Str bonus that can be added to Horn attack (plus Goring Rush or Hammering Horns). I would think a tabaxi unarmed claw strike would necessitate not holding items so no significant advantage there (again, especially compared to a Bite or Horn attack).
Yes, it would be more 'optimal' for Tabaxi to be able to be able to use Dex with their claws. Just like it would be more optimal for Rogues to be able to finesse longswords for example.
Its unlikely to break anything in the game if they did.
I think the reason that they didn't give Tabaxi claws the finesse property is because they didn't regard them as a finesse weapon. Just like they decided that longswords weren't a finesse weapon. Its a commonsense ruling rather than a optimisation or game balance ruling.
Note that the Aaracocra can use Dex with their clawed unarmed strikes, but can't sneak attack with them. There is a distinction between "can apply Dex modifier" and "finesse".
Now personally, I straight-off houseruled away the finesse requirement of sneak attack. However I probably wouldn't give unarmed strike/Tabaxi claws/minotaur horns etc the finesse property.