So what makes for a good list?
If an opponent shows up with a list full of Pyrovores and Hormagaunts led by Old One Eye, most in the community will question why was such a poor choice made. Often to a point that is bordering on degrading to the player. Why then is the reverse of that situation also held with such distaste. Mono Nurgle, Helldrake spam, Waveserpent spam, etc gets the same level of negative response or worse.
Why is that everyone tries to justify there own lists while vilifying the opponents list? Warhammer 40,000 is not now, nor will it ever be balanced. If you want balance play chess. There is a quote floating around that if you find your self in a fair fight then you need to change your tactics. This has been true for every real battle ever fought, it should hold true for a futuristic war simulation as well.
I do not advocate WAAC, if you have to exploit by cheating with movement, pivoting vehicles to gain an inch, or some other such shenanigan then you need to improve on your own skill level to drop such crutches. I often feel that the current editions permission to use allies is a huge crutch to most players and allows for exploitation. Most army lists were written in an attempt to give each army a feel; they get something they specialize in, as a trade off they often have a few weaknesses. With the addition of allies you often see nothing but the strongest combos from each codex.
I feel that there is a time for soft fluffy lists, that time is when teaching the game to a newcomer. Those are called demo games. Would you feel better about your most recent victory if your opponent afterwards said, yeah well I was holding back and used a subpar list on purpose? I see on message boards people using the fluffy list excuse for 2 reasons; either to make themselves feel better about their loss, or to pump themselves up even more in a victory. Why not just build a list be fair and honest and try to win while being a good sport. No more crying about fair or not fair, spammy or not. Do what every military has tried to do; win!
Some of my most memorable games have been against damn hard lists ran by skilled players using Dark Eldar Raider spam well before the internet was all abuzz about MSU/transport spamming. And that was 3rd edition.
Calling a list or player fluffy or WAAC is bad sportsmanship. Cheating and rules exploits are bad sportsmanship as well.
Get out there and try new lists, shake things up and work on new combos within your codex. Who knows you might create the next great net-list that everyone talks about.
