I don't think they should scrap the supercarriers, not at all, but I do really think several cheaper ships alongside those big ships would be a good idea.
Look at ISIS, if the US wanted to bomb them it has to send a 100,000 ton ship surrounded by appropriate escorts in order to drop maybe 4-5 bombs per day, often less. Thats a massive expenditure of money and gross overkill. It's also both risking a major asset for a fairly unimportant task and taking a premium ship away from its main job of dominating the sea lanes.
We don't even have to look theoretically, in WWII CVE and CVL classes were often assigned to support ground troops while the fleet carriers roamed off shore hunting for Japanese warships. They could do each others jobs of course but the whole idea of a CVL is to free up better ships for their primary role.
You can also look at Vietnam where you have bigger carriers projecting power while smaller ships were on call for close air support. You could and did have ships like Enterprise offering support, but a modernised Essex could and did fulfil that role just as well.
So that is sort of what I'm looking at, define what you want your ships to do and then send the best design for it. A Supercarrier is there for power projection, to seize control of ocean routes from a viable enemy navy and then attack enemy territory. A smaller carrier wouldn't do that job as effectively, so there is a role for these big sticks.
But carriers have other jobs. With the advent of helicopters carriers were tasked as helicopter assault platforms. They still can do that task but it would be a waste to deploy a Ford for that job, so the USN made ships specifically for that task.
Carriers also conduct large scale ASW missions and do so very well, but again you send a CVN to hunt subs it is a huge waste, and risky, so you use smaller custom made ships. Well, technically you get NATO allies to do it instead with their dainty Cold War carriers with secondary Harrier capacity, or those Japanese 'destroyers'.
Carriers are also there to support allied ground forces in low intensity wars, but again if you are only dropping a few bombs per day and you are tied to a shoreline that's a waste of your big ships. LPH's have a limited air support role to cover some of this, but the USN has already scaled back on this in its next set of assault ships leaving a potential gap in ability.
So for set piece battles and power projection, a Supercarrier is great, but for all the other jobs a carrier needs to do especially as those roles become more common and important in the future a giant ship is very inefficient. I'd say there is definitely a niche for a multirole ship bigger than a LHA but smaller than a Ford.