Like 3 years ago this card was "Wow, if you get 3 allies, you get +3 cards, that's new staple". It is (partially) true but today... I think hero need to be at least solid in defense to include Strentgh in Numbers. For example if you had 2 allies on the board (and 5-6 left in deck) what is the probability to draw a ally? 33% or even lower. More so you need to focus in deckbuilding to create the possibilty to play this allies. Playing only 1 hero there is no that many situation, when this card is more beneficial than many in Leadership aspect. Don't get me wrong, this is good card, but not A-tier (not any more)

In solo this card is (A-C) B In multiplayer A (if you focus in create heavy-allies deck)

After 150 plays, this is for me the black lotus of Leadership. Even getting 2 cards for 1 is a deck thinning possibility that I would consider. A 1 health ally is better used for 1 draw and chump blocking than 1 or 2 points of damage.