Thank you very much for this series, it already feels that it's going to be incredibly valuable!
Spoiler
1) Myth and realities
I feel that my biggest problems are calling too many weak hands preflop (vs a raise, a 3bet, or even a 4bet) and ending up folding them after the flop. Or maybe I'm not playing aggressively enough. I should be 3betting more as well.
2)Printing money preflop
Using w34z3l's methods to find out the strongest hands I'm folding I saw that vs a CO open I was folding stuff like AA/AK and other premiums. So it means that I timeout too often and that I should either play less tables and/or avoid distractions. Maybe it's a good idea to go from 6 to 4 tables for a while, during the learning process, and of course no more YouTube/forums/Skype while playing.
That being said I saw that I regularly fold hands like AT on the button vs a CO open, these kind of hands can clearly go into my 3betting range. I will also 3bet more offsuit broadways and call the suited ones. The reasons behind this are:
a) When I call I'll play without initiative so hands that have more playability are better
b) I run the risk of getting a call from SB and/or BB, and a hand like KJs plays better in a MW than KJo
c) I open the spot for a squeeze, I prefer to hold QJs than QJo if it goes SB folds, BB squeezes, CO calls, Hero...
Filters: Hero is BT, 1 Raiser on the CO, all pairs, all suited broadways, A9s, most broadways.
So I clearly need to pay more attention to the tables, folding hands like AA/AK/QQ is not really acceptable. Moreover, if I'm folding AA preflop I'm certainly making similar mistakes after the flop, and on top of folding strong hands I must be too passive whenever I read forums/talk on Skype and look at my hand strength, I'm probably thinking "oh well, he bets and I have a weak hand. I fold".
3) Blind Efficiency
So this is interesting. I guess preflop I'm fine-ish, I could be 3 betting more and probably cold call less. It's not perfect but very good compared to the post-flop leaks I have. I have a WWSF of 41%, and the Hero in the video had 42,6 and w34z3l said in was very low! He said as well that the "flop raise cbet" should be around 20% and I have 5.8%. Basically I'm sticky and annoying preflop but that doesn't really matter as I'm relatively easy to play against after the flop, I'm folding too much and not raising enough.
BB vs SB play: I believe my winrate is decent there, I defend over 50% of my hands and make -19bb/100. It may even mean that I should defend wider, because if I fold I lose -100bb/100, though if I call and lose -80bb/100 with weak hands it's still very profitable. But I'm exploitable vs cbets, basically some villain could 3 barrel ATC and I'm folding enough on every street to make it profitable for him. My W$WSF is <40 as well, which is very low. 
BB vs SB
And now the BB vs BT play. I lose more, I'm tighter, but I fold even more on the flop and river. My W$WSF is even lower. I forgot to add it to the screenshot but my "flop raise cbet" is 5.85% here. I guess again I could be 3betting more but the main problem seems to be after the flop. But how can I put my opponent in tough spots when :
a) His range is stronger
b) I don't have initiative (thus a capped range)
c) I'm OOP? (BB vs BT play)
BB vs BT
Hopefully I will have answers in the "Question Time" video. There might be other problems as well.
I'm thinking that I could be CC'ing too much, w34z3l says 11-13% CC is standard and I'm at 17.6%, which is about 50% more.
CC% per position
Now let's see when I have CC=true. My MP and CO CC feels too high, how could I flat a 12.3% range vs UTG with 4 players left to act? Sure, sometimes I flat AA/KK but I'm still left with a bunch of relatively weak hands.
CC is true
As we can see, I have a very low W$WSF, and I fold a lot to cbets. I decided to run the same filter, and I just removed JJ+:
CC is true, excluding JJ+
Aha! So I guess that's good news. Last year I lost money in every position except BT when I was cold calling TT-/AK-. I mean that it's good news in the sense that I have found something to work on. I need to reduce the hand range with which I cold call preflop, and I will automatically lose less money and have a better redline, simply be folding. It will also help me focus on my other tables and I won't fold the ATo OTB vs CO open anymore :D, so it's a win/win/win situation!
4) Multi-way pots
I feel I play decent in MW pots, vs PFR at least. I may not cbet often enough, for example he said he'd cbet the A3hh on the Q84h board BT vs SB+BB, saying we have BD draws, but that feels super loose to me. Maybe we get a ton of credit on our 2nd barrel as well, not like HU play, I'll experiment cbetting more flops.
Hero is PFR in single raised pots 3-way
Though when PFR and facing a 3bet I have a very low winrate, I'm at -278bb/100 OTB, which means that I lost more with hands compared to a call, given that my standard is to open 2.5x. So it's back to calling too much 3bets with weak hands and being pushed out of the pot.
Bonus) Question Time
Well it was good though nothing that really answered my questions, I should have started to work on my game earlier!
5) Free Money
Wow... I just checked my graphs with the first filter of the video (IP and villain checks twice to us and we check back twice) and I'm losing a lot of money when it goes xx flop and turn. Though when I bet I make a lot more. It's quite crazy.

It gets checked twice to me and I check back
And...
It gets checked twice to me and I bet turn
So this is a big thing!
And when it goes xx flop and I'm OOP:
- I made 142BI out of 3500 hands when I bet, that's roughly 40BI per 1k hands or 400bb/100 winrate.
- I made 21BI out of 5.8k hands, so 36,6bb/100.
So this is some big discovery. I guess all this time I was afraid to face balanced villains, like, it became quite standard to check back hands like A2 on Axx, or that they won't fold the JJ on Q9xx vs 2 barrels, and that if they call 2 barrels I will run vs KK/Q2/etc. I will experiment with that during the next few weeks.
Edit: My "profile": been playing 100NL for 2 years now, lowish WR and I want to move up.