delericho
Legend
If we're going down the "reduced cost" route, it would be more efficient to reduce the game from three $50 books down to one $50, rather than from three $50 books down to three $40 books. (Which rather assumes that WotC haven't done that already.)
In order to achieve this, I would happily sacrifice setting-specific races (IMO the Kender, Warforged, and any other such races shouldn't be in the PHB anyway), all but maybe 8 classes (no need to cover everything from every previous PHB), and especially the high-level material (which is, sadly, likely to be insufficient anyway). Heck, if you assume the Starter Set is for newbies then the PHB can be assumed to be for experienced gamers, so you can ditch the basic "what is an RPG" stuff also.
In order to achieve this, I would happily sacrifice setting-specific races (IMO the Kender, Warforged, and any other such races shouldn't be in the PHB anyway), all but maybe 8 classes (no need to cover everything from every previous PHB), and especially the high-level material (which is, sadly, likely to be insufficient anyway). Heck, if you assume the Starter Set is for newbies then the PHB can be assumed to be for experienced gamers, so you can ditch the basic "what is an RPG" stuff also.