As someone who has struggled mightily this year in RCL 5, the second most "competitive" league according to the indexing, I decided I'd give my short input to this conversation as well.
Back in May, before my team went through a plague worse than anything seen since Biblical days, I was shifting back and forth between 2nd, 3rd, and 4th place in RCL 5. As Buster Posey, David Wright, Jonathan Broxton, Jorge De La Rosa, Roy Oswalt, Jonathan Sanchez, Chone Figgins, and several other non-factor late-round players hit the DL, I tumbled HARD into last place and sat there for quite a long time. I never once have given up on my team, but it seemed like no matter what I did, I wasn't able to pull out of last place.
Every time I went to add a player, someone else had grabbed him 10 minutes earlier. Every time someone went on waivers that I really wanted, someone with a higher claim grabbed him. The league index system is obviously not perfect - there's no such thing - but it does seem to do a good job at reflecting how good a league's competition is. Now that a few teams in RCL 5 have given up, it's been easier to grab players up and improve one's team, though I do shake my fist at Random Italicized Voice for snagging Rafael Betancourt off of waivers this past week.
Thankfully, with the perhaps lessened state of competition, the return of David Wright, and me having traded for Jay Bruce, I've been able to move out of last place and I hope that climb continues at least a little bit, but I can attest that at least some of the cellar dwellers are still competing and checking multiple times per week, and that the competition that each league brings to the table does make a difference in how someone's team fares throughout the course of a season.
12 Team H2H, 4 unrestricted keepers
C - Mike Napoli
1B - Eric Hosmer
2B - Jedd Gyorko
3B - Todd Frazier
SS - Jhonny Peralta
OF - Ryan Braun
OF - Mike Trout
OF - Shin-Soo Choo
UTL - Brett Lawrie
UTL - Adam LaRoche
Bench - Austin Jackson
DL - Aaron Hill Hanley Ramirez
SP - Clayton Kershaw, Madison Bumgarner, Ubaldo Jimenez, Jhoulys Chacin, Ervin Santana
RP - Glen Perkins, Heath Bell, Jose Veras, Ernesto Fireri, Edward Mujica, Carlos Marmol, J.J. Putz
RCL - Cracking the WHIP - Admiral Trey
C - Yadier Molina
1B - Albert Pujols
2B - Jose Altuve
3B - Jedd Gyorko
SS - Jimmy Rollins
MI - Everth Cabrera
CI - Justin Morneau
OF - Jason Heyward, Shin-Soo Choo, Michael Morse, Nick Swisher, Ben Revere
UTL - Kendrys Morales
Bench - Garrett Jones, David Freese
SP - Justin Verlander, Cliff Lee, Ryan Dempster, Ubaldo Jimenez
RP - Jonathan Papelbon, John Axford, Glen Perkins, Ryan Cook, David Robertson