Why do only some lines have a Tier X grind?

[Edgecase]

I'm sure this has been asked before, but why do some Tier X ships come with their final upgrades, and others have large amounts of additional XP requirement unlocks?

 

Examples:

 

Yamato: 249k to research, comes with everything

Hakuryu: 248k to research + 126k to unlock all upgrades (96k if you only take one flight control)

 

Gearing: 236k to research, comes with everything

Shimakaze: 226k to research + 60k to unlock all upgrades (30k if you don't buy the knife fight torpedoes)

[Rusty_Bucket__]

Perhaps there is historic rationale for providing the different levels/features.

[Lert]

Hakuryu and Shimakaze have sidegrade options that are not necessarily better or worse than the other ones. WG has elected to make them available for research.

[Goose21891]

WG did the same thing with some Tier 10 tanks, i.e. E-100, M48

[Gavroche_]

Hakuryu and Shimakaze have sidegrade options that are not necessarily better or worse than the other ones. WG has elected to make them available for research.

 

The CVs get straight upgrades to their planes. They get +speed and +health 

[Naviss]

I think T10's should get some upgrades honestly.

[BlazerSparta]

WG decided that a reduced earning ratio wasn't enough to slow down CV progression in their early OP-ness, and gave CVs extra roadblocks to hitting max potential.

[ryuukei8569]

To my knowledge, Simakaze and Khabarovsk are the only non CV's at t10 that have upgrades, but their upgrade options are more side grade options rather than upgrades. As for why they force the T10 CV's to have to endure a plane upgrade grind. I have no idea, maybe its done on purpose to force some matches to be uneven. Or to force T10 CV players to fork out money to purchase the free XP to get past the upgrade, and since CV's are the most tier sensitive, where even being outtiered by one tier leads to being roflstomped, CV players are the most likely ones to try and Free XP past plane upgrades. Its probably the latter.