(I am a fan of the Yakuza series and have been since the start, so don't assume that this is coming from someone eager to trash the game. Though with the past couple games I've gotten a bit more critical of the series, I still have fun with them and am looking forward to Yakuza 5...that said....)
Well the visuals have been noticeably stepped up, which is good, especially as far as the lighting goes, I agree with Shigs there. My issue is that it all still has a very "basic" look to it, certainly not up to par with the lovingly detailed Sleeping Dogs, for example. The lighting's nice and adds a warm glow (when he's walking in the park, for example, the graphics really shine) but when going through the streets, I dunno, things still seem a bit too sterile, too boxy. A little disappointing that this is the best Sega could do, ditto for the text boxes, which seem as outdated as ever.
And I dunno. From watching the demo it doesn't look like things have changed that much, if at all. This still seems to be the same Yakuza game we've been playing since the original. I mean, it's not a bad thing, necessarily, but with all this talk of this installment bringing change and evolving the series, this demo sure doesn't seem like it.
Those are just my thoughts anyway. It looks like it'll be more Yakuza fun, but I'm disappointed by how familiar it looks.