What's Wrong With Lawful Good?

[King of Nowhere]

I believe the 'evil manservant' thing was in terms of being adjunct to a good character, not another evil character.

Right, my bad. well, perhaps there is the good lord, and there is his manservant slaying his foes without the lord's knowledge. a good example of how that could have worked in the past is with thom merrilin from the wheel of time. when rand had just taken over the nation of tear, thom started to forge fake proof that some lords - all of them opponents of rand - were going to betray each other. in the next book, all those lords had assassinated each other, before they could seriously oppose the protagonist. and the protagonist never figured out about it.
the "urchin criminal past" is still on the table.

Despite one rather impressive showing for team Good (figuring out a way to work with an Illithid), all the other instances of people saying, "I don't see how that could work" is a better answer to "what is wrong with Lawful Good", a better demonstration of their intolerance in action, than I could ever hope to give.

The average player is neither sufficiently skilled at not in the right mindset to look for ways to make Lawful Good work. As evidenced not just by my own extensive experience, but by the number of times Playgrounders - a site which generally bats above average, IME - have gone on record (in this thread, and others) saying that they don't see how (Lawful) Good could work with X.

I am growing more and more apalled by your attitude of "if you can't work with a guy who routinely mindrapes, kills and eats other sentient beings, it's your problem". I would say the problem is on the guy who does the other stuff. I would say it's the mind flayer that cannot play with the paladin, not viceversa. (barring some extreme "foes have to unite against the end of the world" scenario)

Your whole "your character won't accept mine, so it's your fault" is nothing but an attempt to guilt-trip people who want to play an heroic fantasy into accepting murderhobos among them.

And NO, you do NOT have the right to play whatever you want and complain about other players curtailing your experience because they do not want you to do that kind of stuff. I have as much a right to say "I don't want to play at a table that does X" as you have to say "I want to do X at the table". Hence session 0. People talk about what they want to do at a table and what they find unacceptable. And if you do want to do X, and I cannot accept X, then the whole group has to decide one way or another. and once a decision is made one way or the other, the character who got suckered by the decision has to either accept it, or leave the group until the end of the current campaign. possibly without hard feelings.
The point here is that the other guy has as much right of not wanting to play a dark fantasy as you have to play one.
Want to play a mind flayer eating babies? find a party that's ok with that. Don't try to shift blame on this one party for not wanting to be part of it

Sure. But the problem is, "alignment" is a poor substitute for "personality".

absolutely true.
and that's why you should not discuss "alignment". You should discuss "tone". As in, "are we going to be the guys who will donate a lot of our loot to charity? Are we going to help poor people for free? Are we going to be the guys who execute prisoners when it's needed? Are we going to be the guys who execute prisoners because it's easier? Are we going to be the guys who execute the prisoners, and then track down their families and execute those too, as a warning to others that may stand against us?
Are we going to stop the bbeg? Are we the bbeg? are we going to stop the bbeg and then make everyone regret the bbeg?"

that's what you should discuss in session 0.
Not alignments.