Are they pushing the idea that this ship is for defence only and will limit its strike capability?
The Japan Maritime Self Defense Force (JMSDF) has decided that its two Izumo-class helicopter carriers will not be fitted with a ‘ski-jump’ ramp to facilitate operations...
www.janes.com
I believe Jane's already mentioned from last year, that their approach will be similar to USN/USMC practices on VTOL. JMSDF track record so far mostly using proven concept being done by USN.
If we see how they develop their flat top, we can see it's like evolving one. From first pair (Hyuga's) that mostly behave as LPH, and Izuno's pair then being prepared for light carriers. Perhaps the next pair is they finally decide on something similar to QE class, who knows. At least Japanese media and forums already shown much larger design for the next pair.
ROKN after their first pair of LPH, now moving to larger light carrier concept then Izumo's. The two models that being prepared shown sky jump usage (as one of them leverage Italian Trieste design). So, perhaps JMSDF will rather see their conversion works on Izumo's as test bed for their next pair of flat tops.
If they decide the next pair name Shokaku and Zuikaku, then we know the next pair will really be full fledge carriers. My guess (looking on political side) they wait for what PLAN and ROKN development move, to find right time to finaly release full fledge carriers. They already prepared 40+ more F-35B. Looking at the size and Izumo's conversion, I suspect only around 8-12 F-35B can be operate from Izumo's. Thus I do suspect they are preparing something bigger, later on.