I've finally found enough time to sit down and post some tidbits about this.
I think that a points system wouldn't necessarily reward users with a "quality" entry week after week. We all know that many times a "quality" photo doesn't even make the polls or win them. So, in my very humble opinion a points system will only "reward" a user that has had the most popular entries week after week. I'm not saying it's a bad idea but, I don't think that it will reward users for the real reasons that a point system would reflect a "champion".
As the "host" of the Rally competition, I was glad to see the change of the single point awarded to making it into the poll only if there are more than 20 entries. So far in 24 weeks of the competition there has only been 1 week of more than 20 entries. I like Brock's idea of the same number of points awarded regardless of the competition. Just because the Rally competition doesn't allow modifications of any kind doesn't mean that it's easier to get a "quality" picture than one that has had hours of Photoshop work done to it. It just means that there haven't been as many hours spent modifying the photo. I'm sure there are some users that spend 3-4 hours choosing the "right" photo to enter in the Rally competition and/or in the "regular" Photomode competition that allows a few Photoshop tweaks.
Someone mentioned that the winner of competition wouldn't be able to enter the week following a win. Again, the Rally competition (and I think the Photoshop competition) is different in the fact that IF there are less than 20 entries the previous week's winner may enter the competition following his/her winning week. Therefore, in these competitions, in theory, a user could win several weeks in a row and pull out to an insurmountable lead over the users that enter only the "regular" Photomode competitions. So are we asking to alter the Rally competition rules so that the previous week's winner can't enter after winning? Not a problem for me but, the ones that enter the Rally competition would also have to agree to that. Maybe a point system will help generate more interest in the Rally competition.
IF a points system were to be introduced, I would suggest that each competition keep track of the points for that competition only. There are some users that enter only one of the competitions and there are others that enter every one of them. Again, if we're looking for "fairness" between the competitions it wouldn't be there. I don't think that an "overall" point system would reflect a true "champion" Photomode photographer. It seems that it would only reward those that enter several competitions a week. If a user wishes to only produce greatly modified Photoshop pictures and only wishes to enter the Photoshop competition and is always in the top 2 or 3 in that competition, he/she would be at an overall disadvantage to one that enters all 5 current competitions. But then again the user may not be interested in the points but, only in winning the respective competition that he/she enters.
So, there again it wouldn't reflect a true "champion" just reward the one (or ones) that have entered several times and/or had the most popular entries. A user may produce the most astounding Photoshopped pictures imaginable but, he/she would be mired in the lower half of the "standings" because he/she only enter one competiton a week. Or vise versa in the Rally competition. The best "stock" photographer wouldn't be in the "running" for the "overall" win because he/she doesn't want to (or can't) enter any of the other competitons. And what of the user that has less time to devote to taking pictures. Again, we'd be rewarding the one (or ones) that can devote more time to entering the competitions than others. Therefore, as I mentioned, a points tally for each competition unto itself seems to be an alternative to an "overall" tally.
In some respects a point system may increase the fun of entering the competitions but on the other hand it may take away from it too. As someone has already mentioned, sometimes these competitions are taken way too serious for what they are. I'd hate to see someone get all bent out of shape because they were only a couple of points behind the next one up and a photo that he/she thought would be picked into a poll and doesn't make it blame the one picking the poll for being predjudice about who gets into the poll. That's another factor that would play into the points....favoritism. There are many things that any one of us can say are good or bad about a point system but, in the long run, there's only one way to find out.