Even if you can assault after deep strike it's still a gamble. You have to place your unit 6 inches from the enemy. Then roll 2d6 scatter. You could easily scatter out of assault range, or even worse, Scatter into the enemy unit and mishap. But I guess it would be an improvement on the current situation.
A good thing I can see if deepstriking a unit with a Icon into play and then next turn moving/running them up to 12 inches away from a emeny unit, (maybe even 13 inches with you have a large unit deepstriking in because you have to make a circle around the center model, thus giving yourself at least one extra inch, but it will take some good eye balling to get that close to the enemy unit so you can charge), you can then deepstrike up to 6 inches from the icon and then assault with no issues.
5 plaguebearers 12 inches away from a enemy unit and then you can deepstrike 10-20 bloodletters in front of them, and get 30-45 power weapon attacks that turn. Sounds fun to me