^She can still be Romani/Jewish and British - they aren't mutually exclusive. Plus, if you read the British tabloids you'd be convinced the place is being overrun with gypsies anyway!
I love me the Dailymail, plenty of well written articles But from the rumours that I have heard they're making her fully English, they could potentially make her of Romani/Jewish background but then again we still don't know what they'll do with Wanda either. They've already done quite a few alterations to the comics (i.e. Stark creating Ultron, Pym not being a founding Avenger) so I don't want them to go overboard on reforming the characters.
I'm going to get irritated by the differences between characters, I hate it when two people are cast for the same roles, especially since the movies are a year apart it's going to confuse some people. Considering the huge X-Men cast Peters is probably only going to get a few lines and just be there hopefully bonding with Magneto and being a dick, oh like father like son. However I can understand their reasoning for the differences since they both have different studios and different distributors for each of the movies. Next thing you know the Fantastic Four reboot will include someone like Crystal who was Human Torch's girlfriend for sometime (played by Chris Evans), and then they'll include her in the 3rd sequel as Quicksilver's wife whilst Chris Evans plays Captain America.