It's difficult to get a good balance between not enough liquid and too much.
If too little we get an awful burn smell. If too much we get liquid in the mouth.
Sometimes with the correct amount i also get a burnt taste.
The atty needs to be broken in, and after a few days of vaping, the dynamics change even more. Further adjustment is needed.
This sounds a lot like too much juice and also too much filler in the cart. You are correct about further adjustments needed, however, I am not convinced that it is to the device itself, but to the methods that the device is used.
My method:
I have a nice long pushpin from my office (one that I use to tack up notes in my cube), I will make a custom cart with a straw mod inside, take the correct amount of filler (less can be more here, just be careful, too little and your juice will go into the atomizer too quickly and flood), place the straw in the corner of the cart so that it goes into the deep portion of the cart at an angle a bit. (Read the thread on the straw mod for details on how to cut the straw, etc.)
Then I take my long pushpin and push back in the corner of the filler, and drop my liquid down into that corner so that it gets to the bottom of the cart, then I take the push pin out, push through the top of the filler in several spots to push out any air, and also to allow the liquid to go further into the filler. Then I top off my cart until its nice and moist on top.
If all is well, you should be able to drain your cart fairly dry, though the bottom of the cart is always the hardest to dry up I've found, so you can always save that juice by pulling out the filler and pushing it through a syringe, then top your carts off with that, or store in an empty bottle for when you can. If you're tasting a burnt taste, your atomizer is not getting enough liquid, if you still see liquid in your filler, then your filler is likely too dense. Always test these things with your best atomizer so that you know you're not dealing with an quirkly piece of hardware.
I am still trying to perfect this, and it's always hit or miss at first, but once I get it right, I can vape on that cart for a while, and the filler stays good for a few days, so the upkeep won't be so bad.
I hope this helps.