17-200 1.8L would be improbable. If they DID make it, you probably won't be able to carry it at all. But I get what you mean.
Canon won't shoot itself in the foot by killing off the EF-S series. What I think is this, the current situation we're having with two semi pro and pro bodies is going to continue as the reach and affordability of the crop bodies is tempting, especially the reach. The entry level SLRs will continue to be crop bodies to entice people in. What I'm really glad is that Canon was forward looking enough to see that FF was the way to go and actively went to that direction. For me, I really wanted the power of digital FF and chose Canon over Nikon exactly for that.
Good job Canon!
Samuel
Hehe sam. You know what I always say to you. Want FF, shoot film lah! (just that it's not digital)
That aside, I would also like to add that there will always be a group of photographers (birders for instance) that will want the additional crop alongside a high-res sensor, so I'm sure Canon will never fully kill off the 1.6x range of cameras.