This is one of the hottest and most debated questions out there right now. Blizzard has said a few times that we shouldn't expect a new hero class with every expansion, but that doesn't mean there won't be in the next xpac.
As far as to what the next hero class would be, many are pointing towards a healing orientated hero class. Arch Druid is a favorite of some folks, however an equal number of people think an Arch Druid doesn't make sense, since it would just be a Druid with what – more Druidness?
The real answer to all this will hopefully be coming up at BlizzCon this year. I, and many other people who follow Blizzard closely, cannot not see them announcing the next expansion and its major features at the convention.
"Are Shockadins viable?"
No, Shockadins are not viable. There is not enough gear in all of the Titan's Green Azeroth to make them viable for any kind of DPS. The talents are also not competitive enough with other specs to make them a good choice. Could a Shockadin spec and gear combination become a fruitful endeavor at some point? Yes, but as I've said in the column before, I think Blizzard has other and better things to work on.
As for your second question you asked, if gold is increased when XP gains are turned off, I don't have an answer, but it's on my list to research. Check back in a couple days!
"Is Recruit A Friend a waste of time compared to the heirloom shoulders?"
Recruit a Friend is God's gift to the alt-a-holic.
I RaF'd my way up to a full complement of Alliance alts. It's quite fun to be able to sit down at the game one weekend and say "I think I'll play a Rogue today." Recruit a Friend gives three times the amount of XP with everything you do. That's 300%. The shoulders (and upcoming chest piece) only give 10%. Recruit a Friend wins every time.
I'm currently using the last bit of my second RaF session I bought with some friends, leveling up toons Horde side. We did this, of course, before we heard about the announcement. I wasn't very happy, but am enjoying the lore and vistas of the Horde nonetheless.
A pro-tip to end The Queue: If you're leveling via RaF right now, go and do the dailies and other quests associated with the Fire Festival. Each quest gives around 22% of a level's worth of XP, scaled with your level. It's amazing amazing XP.
Have questions about the World of Warcraft? The WoW.com crew is here with The Queue, our daily Q&A column! Leave your questions in the comments and we'll do our best to answer 'em!