I haven't watched any of the english dubbed episodes, though have watched most episodes in both korean and french. A lot of the attraction of the show is in the relationship between Marinette/Ladybug and Adrien/Chat Noir, so understandably it's not going to be for everybody. That said, the show's really very cute and pretty enjoyable in my book. I find it's a good little pick-me-up show.
That being said i agree that nothing much has been explained in regards to how everything happened. Thomas Astruc, the creator of the show, has promised there will be at some point a origin episode. I'll be bummed if i don't get to see that this season. However it has been speculated that most of the first season is more or less going to act as filler episodes to appeal to tv stations, where they can show them in any order compared to having to broadcast them chronologically - which makes it easier to fill up whatever time slots they need filled or whatever.
As opposed to the original PV while there's some aspects i do like, there's actually quite a lot i am happy they got rid of. I really prefer the CGI as opposed to the 2d animation, i find the art style far more refreshing and pleasant to look at. I'm also pretty glad they got rid of Felix, and swapped him out for Adrien. Felix's personality is such a crusty and overused stereotype, and i really didn't need a snobby and mean male lead once again. As to why it was changed, it was determined by the broadcasting companies that they needed to slightly lower the target audience age and make it CGI in order for it to go into production. While i do hope some slighter darker aspects make some sort of appearance, i don't think it makes much of a difference for me as i still enjoy the show as it is.