Guns to Kill People, People Kill People. The premise of the article is that an army list alone doesn't win a game. It requires a player, rules knowledge, startegy, and yes, a little luck with the dice. I hate it when I see a post or comment on a forum that bashes an army list simply because it doesn't fit a set criteria for a competitive list.
So what needs to happen when list advice is asked for? I'm glad you asked!
1) When a person proposes a list, they should also supply some kind of overall strategy for the army. What do you hope to accomplish with the army? How do you propose to win the three main BRB missions with the army? What weaknesses do you see in the army? How do you plan on protecting them? Give me an idea of how you want the army to run. This gives me some ammunition for helping you refine the idea. You want to run an army of elite Blood Angel jumpers. Let's talk about how you plan to do so. You want to spam razorbacks in a Space Wolf list. Tell me how you plan to cross the board.
2) Tell what units you have to unconditionally keep. In my Sanguinary Guard army I must have Dante and Sanguinary Guard. Done. If you want hordes of Thunderwolves for your Space Wolf army, tell me so.
3) Tell why you are seeking advice. Are you wanting to know if it can go 5-6 rounds undefeated in a competitive event? That's a toughie. Do you want to it for a local 3 game, 1 day event at your FLGS? Do you want to run a theme-y army that can put up a bit of a fight? That's a lot easier.
4) Be prepared to hear criticism. Then take it with a grain of salt. You may hear some things you don't like. That's cool. If you think something will work in the army, try them out even if you are told they won't. If you don't feel particularly attached to a unit and are told to drop it, do so. Go with your gut.
For those giving advice:
1) Try to get an idea of what the person asking for advice is trying to do with the army. Get a feel for the strategy they want to use. Put yourself in their place.
2) Try to stay true to the original vision. If it just can't be done, fine, but if it can, don't squash the idea.
3) Give advice for where the person is. If the asker isn't a tournament goer, but wants to win games, don't tell them their army won't work competitively. Help them understand how it can put up a fight.
4) Be kind. Understand that different people have different playstyles and that they may actually be able to win with a list that doesn't look all that great to you.
Here's the deal. There is no overarching metagame for 40k. Sure. Some armies are grossly underpowered, but they can be made to play well in the right hands. Various areas and gaming groups have different dynamics. Whose to say a Necron army can't be the best army in a group. Whose to say an Imperial Guard leafblower army won't lose with regularity in a local area of gamers. Lists aren't made in isolation. They are made within the premise of their authors' understanding, experience, and preferences. When giving advice, try to help a person achieve their goal. That is what most people want. They want their ideas validated, not to be crushed into the interweb netlist machine. Allow some creativity and individuality for crying out loud.