I see no reason to own the 24-70 or 24-105 on a crop body with the 17-55mm around. It is as sharp slightly lacking range but is fast and has IS. Only thing it misses is weather sealing, had mine in all sorts of conditions, soaked dry etc only thing is it does suffer a little with dust but chuck a UV filter on the front should reduce this.
Reason for my opinion is I did the same thing wanted to go FF in the future so got a 24-105mm and it was great on the long end but constantly switching lenses for the wide what do you combine it with? The equivalent focal length is 38.4-168mm, combining it with a 10-22 there is a huge gap. Buy a 17-40mm in between equivalent of 27.2-64mm Dont get me wrong the 24-70 and 24-105 are incredible lenses but the dedicated EF-s lenses are more suitable. so 3 lenses for a standard focal range... then you need a tele because 168 is ok but not that far so a 70-200mm equivalent of 110-320.
I decided to sell the 24-105mm got a 17-55mm had the 10-22 so that filled the standard zoom range. Also had the 70-200mm so there was a gap on the other end between the 55-110 but depends what you shoot I dont shoot portraits really apart from the odd wedding so filled that with a 50mm which is 80mm equivalent and I tend to shoot on the wider side.
Also the 17-55mm are high in demand, buying one and selling it you shouldn't loose too much money. Most are selling second hand in the UK for between £500-£650 depending on condition.
If your moving to FF then sell it and change up to the 24-105 or 24-70mm. I think that the only FF lenses worth having for a crop body are the teles 70-200 and everything above, the 100mm L or non L macro, TS because there is no crop equivalent For wide and standard the crop sector has it covered, the 17-55mm and the 10-22mm are a fantastic combination. The standard and even the wide full frame lenses are not wide and offer a strange focal length meaning you have to learn to shoot in an unfamiliar way.
My kit fills most of my need for crop, the obvious drawback is to sell the lenses which is an inconvenience not a deal breaker.
50mm = 80mm
100mm L macro
Suits my style but would be nice to have a medium tele in the range at events but they dont make a fixed aperture just the 15-85mm try to stay clear of vari aperture lenses.
If they made a 15-85mm 2.8 I would be all over it but they wont, im guessing because it would sacrifice all the other lens offerings although im sure the price would make your eyes water. Plus not many pros shoot crop for everything more for the tele end and reduced cost of lenses so less need I suppose.
Best case have a 7D for length 5D MKIII for everything else.