If WePay intends to overtake PayPal, I think it will need to do more than that. An "appealing design, an expedited set-up process and better customer service" are easy to replicate.
How about thinking out of the box and re-engineering the system? How about focusing on and addressing PayPal's weaknesses? How about creating a system that inherently includes automatic fraud prevention (for both buyers and sellers)? How about minimizing (nearly eliminating) all dispute resolution scenarios? How about extending such protection to the services marketplace (as opposed to just products)? How about creating a truly globalized payments platform (there are several countries where PayPal fails because credit cards are not used or available as the main form of payment)?
I am a co-founder of a nascent third party payments aggregator (TPPA) called PayGuard. We are currently building our Beta, and our system addresses all these issues.