Really just seems like, as is the case with so many other websites, it is a change for no particular reason.
I usually only go there to get some statistics but I like the new design after a superficial look. Doesn't look cluttered and much "lighter" than the previous red.
For middle European standards it is way too much statistics. Pretty obvious they made this makeover for the overseas community.
Ah, I went to Bundesliga.de not Bundesliga.com. They have a different design. The .com version doesn't look indeed like a German website. Well, it is run by Sky not the DFL like the German site. The statistics part on Bundesliga.de looks the same as last year. It is more extended than you are used to, but I like somethings.