Only you can answer that.Good idea or rubbish?
Bear in mind that if you swap your 50 for a 24-105 you'll be going from f1.2 to f4. Quite a jump if you really need the low light ability.Some good thoughts there but I think a zoom would be handy. Maybe a 24-105 is a good option.
Thanks for the answers.
I agree, I have both 24-70 and 24-105 and the 24-105 is still in the 5d2 kit box.As much as I love my 24-105, being in your shoes I'd be inclined to sell the 50 1.2 and replace with 24-70 2.8 L
You'd probably find that the f4 of the 24-105 too slow, especially as your current glass is very fast.