Having three classes that only do damage is pointless when there are other things to consider when it comes to monster progression.
Why not make a new class? It seems to be working just fine at this moment in time. Games hardly go over 1hr 30, and that is with a game full of players who know what they are doing. Games used to frequently make it over 2hrs so I don't see what the problem with monster progression is?
I presume that they will add the goblins in the summer update, which would mean that there will be an influx of new players if they actually end up advertising it. This would mean again that the game time would decrease. Being fixated on monster progression with the current state of the game is the wrong way to look at it.
Dwarf numbers, Defences and Gold all help end or prolong games.
The gold update had the sole intention of shortening games, the "teamwork" thing was just an added bonus that let Rob change things without too much drama around the time of the shields thunderstorm.
If there are very few dwarves, it is pointless having all the monsters dealing damage if they have a PROC hall that can be easily held. Monsters can't kill them because they have the advantage and as long as they have gold they can hold that hall for as long as they like.
You know who gets all the kills at the end the majority of games? Creepers.
Destruction creepers are required for the game to progress as you cannot rely on Special Monsters to do so.
Then let it carry on like that. If you combine the two then it will be OP and unfair to the dwarves who have already been severely punished due to the gold and shield update.
Having a class that specializes in removing defences is integral to progression, if everyone chooses a damage spec creeper then the game isn't going to progress.
As said before, there is no current problem with progression. Just because games are frequently getting over 10k, that doesn't mean it is taking long time wise. When was the last time you saw a game going over 3hr? Or even 2hr?
This is much the same as how Rob has hinted at mobs that can steal Gold, these would be just as important as Destruction Creepers as they help end or progress games.
I'm not sure I agree with this one. I think that the gold situation already heavily favours the mobs.