You can most defintely not turn-off your XP anymore, the ability has been removed from Starter Accounts (the eliminators will not show you the option to, either).
Hordies can 'get around' this as far as (some) Craftables are concerned by camping the Tranquillien vendor (Herbs, Ores; note that the Tranquillien Flamberge - also available from Friendly - is 'deceptively' Green, it's more powerful than it might look at first glance), the Cloth Vendor in Silvermoon, and the Leather Vendor in the Southern Barrens.
Alliance toons will have to rely on Fishing (the amount of Wreckage pools in lowish level areas seems to have been lowered, however), possibly the Darkmoon Faire Vendors (no idea wether the new DMF still offers the Exotic Goods) yet can camp Treasure Chests in Ally-friendly places at low level (only getting a truckload of XP from the Chests).
And of course Grouping etc. allows for some XP-avoidance as well.
But yeah, if there is one thing I'd like to change about Starter Edition rules it is re-instate the option to Lock XP (raising gold-cap to 25 is a close second)