I like the slickness of the new reputation graph, but I would still like a line or area chart that shows accumulated reputation over time.
If it makes programming easier, I think there is no problem at all with using a block line or block area chart. That way you could just change the numbering to be accumulation and then remove the spacing between bars. Should be very simple to have another chart like that and I think it makes more sense, at least for lower activity users.