I hope Samsung would enable carrier aggregation because it's already supported by exynos 9611 chipset but Samsung has locked it.

Please, proceed without wasting a second.

No man, I am not facing any problem after updating to UI 3.0. even my many apps are under deep sleep but they don't create problems.

really but I don't feel drain even I feel battery backup getting pretty much awesome.

First of all if this happening in playstore please clear data and then update your apps from there.if download getting paused after when screen get off it's mean you have blocked background data usage for that apps. so please check it carefully.