Really dumb idea
One only has to look at the mess in the US to see why removing the SIM form the GSM spec is a dumb idea. As it is now, I can take the SIM from one phone and use it on another (unless it is a nano SIM, which only apple uses), if needed with an adapter to fit a micro SIM in a "regular" mini SIM slot. I can just buy a phone on the shop, without contract and without paying the extortion interest rates of a "subsidised" phone.
Without a SIM I would be stuck like those poor suckers using the inferior tech over the Atlantic, as I would have to ask one operator very nicely to accept recognizing my new phone as being the replacement for the old one. That might even be impossible if I bought the phone from another operator, who wouldn't release the phone without paying a fee or even at all.
So thanks, but no thanks. SIM "free" phones have already been tried. In Brasil they were dropped, replaced by GSM phones. In the USA, they are still used, as the carriers prefer to have their customers tied to their service. Lets keep this ridiculous idea away from phones on the rest of the world, ok?