Sol´s Bulwark rework

[Tippa]

Alright, seeing how this item is literally in every single game since it actually is really good item I was wondering if it may be too good on some heroes. One of them I have in mind is Keeper Of the Forest.
Since he can farm in jungle basically risk free and non stop people usually get this item rather early to push lanes. So why should this item, which is meant to be bought as a "team item" be so good on heroes like Kotf?

So my suggestion would be to make it charge based, seeing how S2 likes charges so much. Here´s the explanation:

You get charges based on how many allied or enemy heroes are in the radius of the item. Maximum of 3 charges. The item itself starts at +2/-2. With 3 ally/enemy heroes you get 3 charges, each charge giving +1/-1.

It may sound rather rough since jungling heroes would benefit so much less than they do now but since it is a team item it should be used as one.

What do you think?
Would be too huge nerf to the item?

E: Changed the amount of charges given by each nearby hero from +1/-1 to +2/-2 maximum of 3. As suggested by [DRD]Repugnance

E2: Changed it again a bit.