Cosmic.Justice said:
Actually, this would significantly change the way Paladins are played as proposed, since it would remove the "one step out of line and you lose all powers" side of the class.
Hence the phrase "in my games."
Note, of course, that the paladin's code as written requires that she ... help those in need (provided they do not use the help for evil or chaotic ends), and punish those who harm or threaten innocents," which covers most of the good deeds that the OP listed.
As for committing a single evil act: It depends on the DM's determination of what constitutes an "evil act." I have only once ever had a paladin "willingly commit an evil act" IMC by my definition of the term, and that's because he was trying to become an anti-paladin. What's an evil act? Plainly, garden-variety infractions of the CoC like lying, cheating, or using poison are
dishonorable acts according to the code, but that doesn't make them evil (and in fact implies otherwise). Failing to respect legitimate authority is non-Lawful, but not evil.
Note that the rules do not say "one step out of line and you lose your powers." They say that you lose your powers if a) you're no longer Lawful Good (reasonable); b) you willingly commit an evil act; or c) you
grossly violate the CoC. Thus, the RAW stipulate a
major step out of line. IMX, someone who actually wants to play a paladin also isn't going to take that major step (unless being a fallen paladin is a desirable character concept for him). If poisoning your weapons is SOP, you flout authority at the slightest whim, and you lie, cheat, and steal, then yes, you're not cut out to be a paladin. But what kinds of threshold violations are we likely to see in play? Killing innocents? Enslavement? Torture?