That is definitely interesting, and possibly a paper project being worked up by the IJN, but one that will not be seen off the drawing board until after WWII. For now, the IJN has a lot of projects to digest:
-The Mitsubishi A7M large carrier fighter, Aichi B7A (slightly larger TTL with a 52' wingspan, designed to carry a 1 000 kg torpedo) carrier strike bomber and Nakajima G8N heavy bomber are all in the prototype stages now and are expected to enter service in 1943. All types rely on new large, powerful radial engines, developed with British engineering assistance. Farther off are the Nakajima G10N "Fugaku" superheavy bomber and a jet program.
-The four
Ashitaka class battlecruisers have been laid down; the high wear on the aged
Kongous prevents any further delays.
-The design for the two
Yamakuni class light cruisers has been finalized, finally. Originally intended to to be a relatively straightforward design built on an
Ooyodo hull with a more conventional configuration, the design morphed into a 15-gun, 700'+ ship on a hull of its own. This too was rejected for being too complicated. Instead, the design that was laid down in late 1941 was a 665' ship on a stretched
Ooyodo hull with 5 x 2 155mm/L60 guns, 3 turrets fore, 2 aft. The turrets and cradles were developed with French assistance, despite outwardly appearing similar to (but taller than) the traditional triple with the centre gun missing. However, these turrets allow the guns to be elevated to 85°, and the extra space in the turret allows for more powerful motors for faster train and elevation and power ramming. They utilize many of the lessons learned from the turrets on the
Richelieu class battleships and
La Galissonnière class light cruisers. In addition to these features, the
Yamakunis also carry two floatplanes and a catapult; and the two 4-tube reloadable torpedo launchers their
Agano class predecessors carried.
-The final
Taihou class carrier,
Kaimon (
"Sea Gate") was originally to be constructed as a fleet support carrier with much larger maintenance and supply facilities and a comparitively small airwing, hence the different naming convention- fleet carriers are typically named after flying creatures. The IJN believed this to be a waste for such a large carrier, and ordered her built like her sisters. Instead, either
Hosho will be reconfigured for this role or one of the later
Unryuus built for it.
-The
I-201 long-range diesel-electric attack sub and
I-400 carrier sub programs are going ahead as well, along with the
Ohka flying bomb for the latter.
The IJN has basically its entire wishlist checked off, and that is a challenge in and of itself. Navy Minister Yonai and now Admiral of the Fleet Nagano's skilled maneuvering managed to get all of this approved by the Diet, but that doesn't do much to alleviate the yard bottlenecks or the fact that the design bureaus are up to their eyeballs in work. The navy really
can't ask for more, even if they wanted to. There are no more major fleet units planned to be laid down for 1943, 44 or 45- as of now, the
Yamato class battleships and
Taihou class carriers are prioritized for completion. Numbers for new
kaibokan have actually been reduced, with older destroyers instead being assigned to ASW.