There isn’t a do it all rifle scope, but some day there will be. Technology always improves and better weapons and technology is always down the road. Half a Century ago the military made the decision that the 7.62 round was more than what was need for most combat operations and changed over to the M16. Not only was the 5.56 round a adequate round you could easily issue 2xs as much ammunition. Combat optics normally meant an optic that magnified up to 10x and were not suitable for use on semi-auto or full auto weapons. That is now ancient history and Eotech gun sights, Aimpoint and Trijicon are up to the task.
There are so many different types of optics from Trijicon that are worthy of being put on your M4 Carbine, but the best one in my opinion is the TA01NSN. The back up iron sights are already there and really are more of a secondary close range optic. The 4x magnification on the Trijicon ACOGS can slow you down under 50YDs and you may be better off just moving your eyes to your secondary sights. No flip up sights or flip to the side. Eotech gun sights are outstanding for short range shooting and seem to be very popular in the Law Enforcement Community. Aimpoint and Trijicon seem to be more geared towards Military operations and longer deployments.