The problem is, that the matchmaking is kind of a vicious circle at the moment.
It gives a good balance, but only if a decent number of all Tiers in the queque.
Now they could increase the waiting times for the battles, but this would bring other people complaining about the waiting time.
Another way is to fill out the missing places with bots, but this would lead to people who would find it boring of fighting bots all the time.
What I recommend is to have a little patience until the tech tree will fix the balance issues. Until then the Patch 0.6.0 is already on its way and will bring a lot nice features.
this is the same issue that tormented world of tanks playerbase:
big spread = the ones in the botton are free kills
small spread= matchs takes ages to start and they have usualy crazy lineups.
after having olmost 10k battles in world of tanks i cant tell you this system is not good since is heavy dependant on the number of players, the moment they get low the battles becomes imbalance wich in turn encourage more people to leave.
at this point the best idea is to keep the wide MM to avoid the above mentioned but add a bonus based on the exp diference between the top and the rest, just a thought:
5k exp diference and 10% less exp than the top ship = 2% dmg/speed/dmg reduction
5k exp diference and 20% less exp than the top ship = 4% dmg/speed/dmg reduction
5k exp diference and 30% less exp than the top ship = 8% dmg/speed/dmg reduction
5k exp diference and 40% less exp than the top ship = 16% dmg/speed/dmg reduction
5k exp diference and 50% less exp than the top ship = 32% dmg/speed/dmg reduction
this is just to give an idea, numbers probably need change.