Okay, I saw today's new episode, and here are my thoughts about it:
First of all, I'm surprised nobody has said anything about the new titles, both main and end titles (BTW, is Arthur's interruption during the end titles actually part of it, or was it an advertisement super imposed during the end like other networks do to their shows sometimes?) Also, did I imagine things, or did they actually list that Amanda girl in D.W.'s class at the top of the cast list? The end titles were a little on the quick side, so I may have looked at it wrong.
I can see what you're saying about Arthur sounding like Brain, but I've noticed something else too, it's almost as if Arthur is going in and out of some kind of really noticable accent, it's hard to determine what, because he's inconsistent with it (sometimes the accent is heavy, other times it's not). At least it's an improvement from how high he was sounding for years and years and YEARS. D.W. sounds pretty good too, but Mrs. Read actually sounds a little different this season, like her voice seems a little deeper. Speaking of whom, why are her ears suddenly bigger?
I really can't get past the animation... I'm sorry, but it's just way too stiff, and like it's been said before, there's too much reliance on motion tweens as shortcuts. It also distorts the character designs as well: Arthur looks off-model no matter what angle we see him from, and D.W. actually looked like she had sharp edges in certain scenes.
As for the stories though, they were interesting to say the least... "All About D.W." was a little cliche obviously, but "Blockheads" was actually quite enjoyable. One thing I couldn't help but notice, though, was Emily seemed a little out of character in this one... when she and D.W. are paired up, she's usually the more reasonable and logical one, but here, she seemed almost similar to D.W. in personality, and even in mindframe, as opposed to being more don't be silly, or you're overreacting, like she normally would. But still, it was enjoyable.
So, yeah, after seeing only one episode, I guess I really can't be too objective in my opinion, but my feelings on the new season are mixed thus far... there are some improvements (better voice actors for Arthur and D.W. despite Arthur sounding like Brain), but there are some sour notes (the stiff and shoutcut animation), so I guess I'll just have to continue watching to really base an opinion on it.