Ruby Sightstone is an Underwhelming Upgrade.
For an extra 800 Gold, upgrading Sightstone to Ruby Sightstone gives the following bonuses:
- 250 more HP
- 1 extra charge for placing wards on the map
Arguably, the 800 gold invested in this upgrade could be used in something far more useful. For example, players can instead buy a Kindlegem, which grants nearly the same amount of health along with 10% CDR at only 50 more gold. It's not to say Ruby Sightstone is a bad item; there are just better items to purchase instead.
In order to make Ruby Sightstone a more meaningful purchase, it could use some better bonuses such as increased stats or increased utility.
As an idea, I think it would be interesting to have different upgrades for the Sightstone, depending on the playstyle of the user. For magic-based users, Sightstone can upgrade to Emerald Sightstone, which grants a decent amount of Ability Power and perhaps CDR. For Tanks, the Ruby Sightstone could be upgraded to give defensive stats like Armor and Magic Resist. Utility based users, they will have the Diamond Sightstone, which have a unique enhancement on their ward like granting a temporary speed-shrine that lasts for 1:00 to 1:30. These are just ideas; I am not asking Riot to implement them.
Regardless, Ruby Sightstone could use some better bonuses than an extra ward and 250 extra HP. It would be nice to change it so that it could be a meaningful purchase rather than a gold dump.