Oh yeah the preview was very good, I reallyloved it!
I became a Negaishipper when Iris saved Ash from dying in the hot glisters.
I used to be an Advanceshipper and I haven't supported Pokeshipping ever since I was a little kid. I respected Gary more when he wanted to become a POkemon Professor too, he's not the cocky and street smart childhood friend rival with good looks Gary anymore and really matured and became more intelligent over time.
I was surprised too and they used Gary's original voice in the English dub.
I don't think that Gary was ever replaced, people just say that, because the main girl or main rival takes the role as the heroine or rival in the saga so it's not really replacing, it's just that they're fitting their roles in each saga.
Yes Barry and Bianca could be related but I personally wouldn't ship them.
I don't know about me knowing the future but it would be exciting and amazing if I did have the power to tell the future.