Transition Metal Cations and H2O

[ERIKTORRESDisc3C]

Why is it that despite the fact that Transition Metal Cations in solutions form complexes with H2O but when you add thing such as NH3 or KCN or NaCl that they replace the H2O Ligands? Shouldn't the fact that H2O has two pairs of electrons that H2O would be more electron rich than NH3, HCN, or NaCl and maintain the bond in complexes with Transition Metal Cations and not be replaced???? I really struggled to understand the conceptual reasoning behind these bonds.

[Theresa Dinh 3F]

I read somewhere that it's because despite H2O having two pairs, the H2O prefers not to share the second pair of electrons, so technically that would make the H2O provide the same amount of electrons as the other elements. Don't quote me exactly on this however. I have also read that a ligand's strength is based on its ability to stabilize its lone pairs.

Also, the more negative an ion, I believe the stronger the ligand will be.