Could we buff regen runes? [Balance]

I've been noticing how weak regen runes are. Even if you use the regen hp per 5 scaling rune it only gives 2 at max level. No more than the first level of defense masteries.

As many people know, that regen basically just adds a little bit to your effective health and is really ineffective at lvl 18 for that minor a boost.

Is there any reason we can't give these runes a buff? I mean it wouldn't even be that broken if someone could go a full regen page if it was doubled (4 hp per 5 at lvl 18). It would allow the regen build to be a thing (in the sense that it will actually do something by giving you reoccurring effective health and combo with champions who have other types of sustain).

At the moment they just seem to do nothing. I've never seen anyone use them. Ever.