On my bowden tube friction is minimal. Sounds like something might be wrong with your tube. It wouldn't hurt to measure it and check if its the right size. The piece of tube that I was shipped was all the right size except for the last 20cm which strangely was a bit more transparent and smaller with very high friction.
Seeing you are using direct drive you should be able to get some fast retract speeds which when properly setup and calibrated should have almost no stringing.
Here [secure.flickr.com] Johann's frog printed on his kossel has very little stringing (none that I can see). I would like to maintain that if you can get the bowden tube setup properly, it has it's advantages. A lot of friction in the tube would certainly mess things up.
Seeing you are using direct drive you should be able to get some fast retract speeds which when properly setup and calibrated should have almost no stringing.
Here [secure.flickr.com] Johann's frog printed on his kossel has very little stringing (none that I can see). I would like to maintain that if you can get the bowden tube setup properly, it has it's advantages. A lot of friction in the tube would certainly mess things up.