5% shares to start the game with is quite a bit considering that it's entirely possible for you to not even be breaking 0.10%/turn within the first 75 turns of the game. Felt like a better idea than just giving them a building or something.
Well, it's completely depending on wether the HDD version is good or bad, yesterday for example I easily took down a deity game with uni ...without ever going HDD on (and finished with 100% shares), simply because getting 50% prod for archery/siege units was not worth losing my 15% overall prod/science :/
And as good as it could be for Nep and her incredibly strong HDD form, her weak point is still her early-mid game, and when you start next to a boudicca with free honor+warrior, or someone with liberty... it HURTS (but i admit that even in the base mod there are big discrepancies).
But yeah, it still renew the game more than whatever free building.