I have become fixated on determining where the cutoff lies, where is defense no longer worth the money? I would like to start a theme league that may help get an answer to this question, but I really don't know what parameters to set. Any ideas? I have been in a couple of leagues of this type in the past, but IMO, with "D" teams at A/A+, and "O" teams at C or worse, and at a 120m cap, the "D" teams have too much of an advantage. I am thinking an 80m cap. with below average AAA, 6/2, or a 90m cap with no AAA. This way, there is not much possibilty of either side being able to draft a team that defies the intentions of the league. What do you think? And, where should the line be drawn, as far as acceptable defensive ratings for the "O" side of things, and how bad should we allow the "D" side to draft? What would make for a valuable, information gathering league? Thank you for your help.

I think 60-65mil is the cap range in which players perform similar to real life. You'd have to play there as thats where the balance of defense and offense meet. Because of the OBP curve, in caps higher than 65mil you should spend a greater % of your budget on pitching/defense. In 40-60mil caps you should spend a greater % of your budget on offense.
So cap matters, and also pitching and defense go together. If you take away my ability to draft defense at a 90-mill cap, I'm just going to spend extra on pitching to make up for it. At a 60-65mil cap this effect should be pretty minimal.

I'd focus more on range than fielding. 

Booger is right though. Maybe the best way to do it is to do 70mil and limit both sides to 30mil in pitching (with no good hitting pitchers). One side could be all A+ range fielders and one side could be D or D- range pitchers. I guess to keep things really balanced, everyone should have a good throwing catcher?

If we go to a $70m cap (with 6/2 ba AAA??) speed teams will proliferate... won't they? Under those circumstances, it would be a severe disadvantage to a team to have to draft a D- armed C. Might it be valuable to compare A+ range fielders to B range fielders? How many more + and ++ plays would the A+ team get, compared to a B range team? How many more DPs? Would that not be more valuable than comparing the extreme poles of the ratings? I'm asking, not telling. Your opinions are certainly more informed than mine.

One possibility would be to create a points pool for defense with D- = 1 and A+ = 12 for fielding and range.  Mandate that teams draft 14 players and defensive teams spend more than 200 points on their fielding/range and the offensive teams spend less than 100.  You could even have an in between team group that has to spend 140-160 if you want to compare a middle ground.  You could caveat that no defensive team take worse than a B+ in anything and no offensive team take no better than C-, and the middle team has to take from C to B if you didn't want anyone to game the points system.

I agree with setting a cap on the amount spent on pitching.  If you are really looking for how the defense/offense matters, you could even tell everyone they have to draft the same 11 pitchers (just pick them out beforehand) and the same ballpark.  This would allow for the offense to be the focus rather than the pitching staff and all the ballpark conditions would be the same, taking away that variable.

Just require both teams to have A+ arms, and then if people still want to spend money on speed, they can. 

Yes, most A+ arm catchers are A/A fielders, but we already know the impact of catcher fielding (we see errors and PBs) and catcher range is completely irrelevant.

frazzman, those are, IMO, good suggestions. jfranco, yours as well. I am having a hard time with this at the moment, because I do not have internet access at home. This will probably be corrected in a day or two. PLease, keep the ideas coming, things are beginning to take shape. I think the common pitching staff is a good idea, for obvious reasons.

How about 6 each of A, B, C, D fielding teams?  Same pitching staffs, A+ arms at catcher.  Make field ratings the only real difference and see where the truth lies.

Its a moving scale.  The better your pitching the better your defense needs to be to keep from making a bunch of minus plays and underminding your pitching studs.  Also position matters...  range is much more cost effective up the middle than in the corners.

Players with good range who can hit.  I wouldn't focus on fielding (errors) .