I also initially disliked the lore change on kobolds because I liked the RP with a prideful underdog vibe with widely-questioned claims to draconic heritage. I now think the separate draconic heritage is better game design. I will miss the old kobold a bit though.
In my head canon for the kobold's draconic ancestry, the +1CHA came from an unmentioned bard genetic link, but I'll probably just keep that to the characters I build that use the bloodline.