traditional aircraft carriers and these will get a lot smaller as drones take place of manned strike craft,
I also believe aircraft carriers will get smaller but not for the reasons you state. I believe that they will get smaller because there will be a greater reliance on vertical lift aircraft, helicopters and tilt-wings. I also believe that aircraft will get faster and have longer range, allowing for lesser reliance on carriers. The politics of flying through nations that might not like to get involved would be solved with aircraft that fly high enough to be considered orbital, and therefore technically in outer space, and therefore flying above "airspace".
Much of that is more about the "how" of shrinking aircraft carriers, the "why" is more about economics. Current carriers are big, slow, and very expensive which makes them easy and tempting targets. For the price of one US Navy aircraft carrier the Navy could have four amphibious assault ships, either choice capable of carrying 80+ aircraft. The amphibious assault ships get cheaper by the dozen but the aircraft carriers cannot, there are only a dozen afloat at any given time which makes economies of scale difficult.
Part of what makes aircraft carriers so expensive is the power plant, nuclear power is expensive. It looks like newer, smaller, safer, reactors which will allow for putting nuclear power in smaller ships, removing the range advantage of the larger aircraft carrier. Addition of jet fuel production systems on board means that they will not need to have oilers come by as often for supplies.
Smaller, faster, cheaper, and still capable of long term missions would be a great alternative to the super carriers we have now. Easier to defend against cannon fire and missiles, due to smaller size. If one is lost or damaged in battle then the reduction in fighting capability is reduced.
I believe your description of sea battles are accurate. The cannon fire is not fast or accurate enough to compete with missiles. Rail guns increase the rate of fire, reduce the weight of the ammunition, and reduce the cost, making it a very good alternative to current missiles and cannons. The range and accuracy of the rail guns might not yet compare to that of the missiles but are still a leap in improvement over cannons.