Shadow Warriors were pulls from "official" list status because all the feedback was saying that they were too powerful.
Three (plus one) warbands that should not be allowed:
Shadow WarriorsI tried playing Shadow warriors and struggled imensely, but I have talked to many people who played much more Mordheim than I that found them to be Broken. I will give my experiences along with what I have heard from others.
In my second Mordheim league I played shadow warriors and never felt like I got the warband off the ground. Here are the problems I ran into:
-High Cost: Elf henchmen are expensive and not any more durable than any other faction's henchmen. I was spending most of my money replacing my dead. I longed for a cheap troop like witch hunters, Skaven, or Orcs can field.
-
Low Strength Attacks: Everything elves do is
Str 3. Bows are all
Str 3. In melee shadow warriors don't have the options other factions do because they can't make good use out of 2 handed weapons because they don't have any heroes with Strength skills. They have good
WS and can get a good number of attacks, but cracking toughness 4 or even 5 is painful.
In my first few games I played against beastmen, orcs, and dwarves. I could not wound toughness 4 to save my life. I was amazed that dwarves could hold there own against me in shooting. Crossbows were hitting me on 4+ and wounding on 3+. I didn't have enough armor to even get a save roll in most cases. I hit on 3+, wounded on 5+ and he got any armor saves.
That being said, since then I have talked with a number of friends who have seen Shadow Warriors warbands that made them scream cheese. I can not discount their opinions. Obviously that sentiment tended to be the consensus over players in general. Here are some of the things they have said:
Elite is better: High Speed, Initiative,
WS,
BS across the army gives them a lot of versitility starting. Their Initiative makes them the most reliable climbers. Heroes especially love higher base stats. There are only so many advancement rolls and shadow warriors will max out higher across the board.
Accurate shooting wins games: Many a Mordheim warband focuses on shooting and elves are more than a little good at it. I can see how Mercenary warbands could fear coming up against the elves.
Dark Elves - see above. They have very similar problems to Shadow Warriors, but with access to crossbows. I must admit I have not ever seen them actually played.
Dwarven Treasure Hunters - Dwarven Axes are way
OP. All the dwarf parry tricks (not to mention hard head or whatever) make them near impossible to take down in melee. I find the dwarf specific equipment and skills to be too extreme. Their slow speed is their main balancing factor, limiting their effectiveness in some scenarios. With a couple good advancement rolls dwarves can be terrifying
And just for kicks,
Skaven - Large numbers, cheap troops, Black skaven!, and the ability to buy a full regiment of 6 heroes. What was
GW thinking

You have to compare everything to Skaven before calling it
OP.
I have heard that the elite factions (elves & dwarves) all tend to be very swingy in campaigns. If you take losses early in a campaign the warband may never recover, but if you have a chance to build up your force these warbands can become nigh unstoppable.