Looking at that layout picture, you might be blaming your speakers when it's their position in the room that isn't helping. For the sake of stereo balance, symmetry is a good thing.
Getting the speakers further out into the room, possibly closer together might help. Aiming for about 1/3 into the room from all perspectives (front to back, side to side and floor to ceiling) is a useful guide. The reason for this is that speakers too close to a wall tend to excite the room nodes, and in a small room with parallel walls, the room nodes are going to be a problem. Exactly halfway into the room isn't good either, not that's its possible with stereo speakers. So that leaves 1/3 into the room a good starting point.
Sound doesn't care about gravity or spacial orientation. So anything that applies to walls also applies to floor and ceiling - consider the symmetry and distances from surfaces.
Seriously - try moving your speakers around the room and listen to the huge differences this makes.
In a small room, serious damping is probably your safest bet, and rely on true nearfield monitoring. You might need to study up on bass trapping, because your comments suggest you may have killed your high end reflections, but might have a muddy room sound if you haven't killed the low end.
Every speaker & room combination will sound different. You can't expect these to sound the same as your car, stereo, or laptop speakers. You will be disappointed in any good set of monitors if you are chasing this illusion.
The trick is to realise that the perfect, flat response, monitoring system doesn't exist, and that the goal is to create mixes that work well on the majority of the wildly differing systems out there. You need to listen "through" your monitors, not "to" your monitors, if that makes sense. If you get familiar with your speakers and room, with successful, well-mastered commercial mixes, you will know what a good mix should sound like - in that room, with your speakers. Then, your goal is to mix so your own mixes sound the same. Not "better", because that will mean you are overcompensating and actually making things worse.
As an educational tool, I think www.harbal.com
is worth a look.
I'm in a similar situation of needing to replace some inferior speakers (Behringer Truths). I've tolerated them for a long time because they actually work, and you can get a lot worse. But for me, the main reason i'm replacing them now is because I can't stand the hum (both acoustic from the transformers, and electrical from the speaker). I've moved my PC outside the room, and now the room is so quiet, the amp hum is bugging me. I actually suspect that a lot of active monitors would bug me too - I really don't think it's smart to have the power amps mounted inside the speakers, bringing them so close to your ears, because AC powered amps hum.
I know the theories of why actives should be good - short speaker wires, tuned biamp electronic crossovers, blah, blah, woof, woof. But if the amps hum, there is no advantage. I find a good hifi amp, like my Linn, doesn't hum unless you put your ear up to, and you can place it well away from your ears.
So my next monitors will be passive. Very probably Dynaudio, because I can't get Adams in my country. I'm not impressed with the specs on the Tannoy Reveals. The Behringers, despite their failings, were surprisingly OK, and I don't want to go backwards. (I had to reject two Behringer speakers to get a good pair - so I don't recommend them to anyone, unless you can test them for yourself).