Hmmm… The strongest argument is the accent, methinks. The rest don’t hold up (Luke uses Jedi mind tricks too, in ROTJ, has the same clothing, except black, you could argue that Han is the Obi-Wan of TFA and also pokes around Starkiller Base etc.)
But here’s one thing I’ve noticed that would lend more credence to Rey being a Skywalker: She looks like her Grandma: http://wp-pbp3.static-cdn.com/wp-content/uploads/2015/04/amidala_and_rey.jpg
I don’t think it’s a casting coincidence that Rey looks so much like Padmé, (and even more like Padmés hand-maiden, Kiera Knightley, but that’s another story). One should also note that the Skywalkers have brown hair, generally. Both Anakin’s and Luke’s turn from dark-blonde to brown as they mature (like my own did…am I a Skywalker?) over the two trilogies, and Leia is a brunette all the way through.
Obi-Wans hair - before he goes grey - is dark blonde-reddish in ROTS, but lighter than Anakins: http://ia.media-imdb.com/images/M/MV5BMTM2NzI5MjgyNV5BMl5BanBnXkFtZTcwMTI1NjI4NA@@._V1_SX640_SY720_.jpg
With a generation in between, Rey could have gotten her brown hair from anywhere… but still. And in both canon and non-canon material, there are no indications (AFAIK) that Obi-Wan ventured anywhere after he retired on Tattooine, and definitely no indications of family.
And then of course, there’s the fact that it seems that the Kylo Ren storyline is lifted from EU, even if they have discarded the latter. They’ve just modified it (as many have mentioned here), so that that it isn’t Luke’s son who is named Ben, but Han and Leia’s, and Han and Leia’s son does not kill his aunt, but his father instead. In the EU, he is killed by his twin sister - he’s likely to be killed by his cousin now.
If this is indeed the case, the Rey Kenobi theory makes no sense. However, now that we’ve pretty much all made the above prediction, the Lucasfilm Story Team may very well change the whole thing. Which would be cool.