There are a few possible common causes for having a decreasing red line:
=> folding the best hand too often. The reason is obvious why: if you call your red line stays at home and the blue one gets up, but instad the blue stays here and the red decreases
=> missing bluff spots. It is in my opinion one of the worst way to try to "correct the red line" (which should not be corrected, you should improve your game and the red line will correct all by itself, the red line can just give you hints about possible things to improve)
=> Missing valuebets: think about it: you have a good hand on the river, but you're not sure you really ahead. There are basically two choices: either you check, and win/lose 100% of the pot in the blue line. Or you can try to valuebet if you think he'll call more often being behind than ahead. In that case, you will get called and the result will go in the blue line, and you will get some worst hand to fold, the win will go in the red line.
=> Missing light calls / bluffcatchs. This could simply go with the first point though.
About the positions: the stats are not that ugly even though it could be improved. I don't think you should really bother about this, these stats are totally able to get a nice winrate at this limit. Working out your postflop skills are much more important than adding or removing a few preflop hands. Also, getting better at postflop play will let you learn and understand why and how you play your hands preflop, and might simply let you get better at it. I think it's better than just becoming a winning player in NL2 thanks to a chart, than having to change chart in NL4. Then rechange chart in NL10...etc... The simpler way would be to understand your prelfop play through postflop, so that you won't need any chart anymore.
About the cbetting without 2nd and 3rd barrels bluffs sometimes might be costly, effectively. I totally agree with you, even though I would not stop this to just the cbeting stuff. This is true with every bluff you make, they can get costly if oyu do'nt know when to follow through. This is the reason why I said in the post than trying to correct the red line by bluffing more is a bad idea: you will end up hyperaggro without sufficient postflop skills to work the best of it.
Donc try to bluff more to get your red line up. There is absolutely no reason the red line HAS to get up. In fact if it is getting hugely up in NL2 you are likely to have huge flaws in your game (calling station?). The red line will adjust itself as your game will improve.