The above is the only stuff that's needed, the rest that you listed are unnecessary distractions (and indeed Nokia had already attempted some of them in the form of the short-lived Ovi)

For me the Ovi Store payment system that Nokia had (ie charged to your phone bill) worked better for me because:

a) I don't want to use a credit card
b) I was able to buy pre-paid sims at up to 80% discount on the stored values and use those to pay for apps (which effectively meant I was able to get up to 5 apps for the price of 1)