Personally I don't think the slight increase in capability is worth the extra 63 tons.
(I knew someone would say that, lol)
Considering I already have a pretty huge and heavy ship, and considering I do want something serious for shore bombardment now that my MLRS is gone, I think the added weight is worth it. After all, the alternative is an AGS...
I think I'll design my own gun however, instead of copying everything from the Russian gun. Will have the same mech, but with a different calibre.
Hitroles are very nice for that.
It doesn't quite have the range of a real naval gun. And it doesn't has that... (how do you call that?) ballistic trajectory... thingie. That, and it lacks firepower compared to a lol-artillery gun.