Not trying to start an argument but maybe they gave him minor buffs because they believe there is more to Z.W.E.I than we think. Or they are scared to seriously buff him because he is one of those characters that could easily turn OP. Either way I expected them to do a little more than this.
If you have the meter you can do 4b BE, CE, b+k, 4a+B. A lot of the options are covered in the the combo threads.
Edit: I didn't realize that 3a BE does more damage than 4b BE. So maybe that is the best route to go into whatever.
I don't know if this is useful/known or not but I noticed something with b+k BE. After you use it, wait until Z.W.E.I recovers from his stance and press b+k again. If you did it right he should do b+k, Ein will go away and then reappear for the original BE attack.