I don't think that they'll discontinue everything. ...just the consumer-consumption-bent Web-OS stuff. --they'll let Apple and Android have that market.
Right-clicking, yes, the press and hold is the old way. On the Slate you can touch with one finger, and briefly touch with another finger to the right. (much like right-clicking a mouse) Try it, you like it.
I've been using tablets for a long time now.... This is better, for a screen-only experience. Now that Windows 8 is out for developers, it's ended up on the Slate. There is a Youtube vid or 2 out there. Search (windows 8 metro slate 500)
here is one story
Windows 8 developer tablets go for $3,500+ on eBay - Computerworld