The way I see it, there are two flaws with the current Top Rated of the Month (TRotM) system:
- There is no competition at the start of the duration, but a great amount near the end
- The amount of promotion each article receives changes based on when it is posted
Getting free promotion on TRoTM has a snowball effect. More promotion means more votes, more votes means higher on the list, higher on the list means more promotion, repeat. This is a huge incentive for authors to post on the first few days, since nobody else is on that list — you're only competing with other people who post with you. It's also a huge issue for those wanting to post later in the month since they will be competing with (read: buried under) all other posts that came before it. It's incredibly rare to see something in the higher echelons of TRoTM that wasn't posted within the first couple weeks.
The other flaw with the system is that not all articles get the amount of promotion. If you post on the first of the month, you are on that list for the entire month, while those that post, say, on the last of the month only get one day. This flaw is synergistic with the first, further driving authors to post on the first of the month, for the full ~30 days of promotion.
Are we surprised authors only want to post on the first of the month? Doing anything else seriously hurts your chances of getting noticed. Authors posting on the first of the month is a result of shortcomings in our current system which is definitely something we want to nip in the bud as soon as possible.
A "Top-Rated of the Week" system fixes neither of these flaws. It simply breaks down one problem into smaller ones. The symptom will be mitigated, yes, but the disease will still fester. People will post more frequently, but it won't fix anything. Authors will still post on Monday 00:00 GMT+0, authors posting on Monday will experience more votes due to the snowball effect, and authors posting on Sunday 23:59 GMT+0 will get no promotion whatsoever. So, naturally, people will spam-post on Mondays and there'll be no content for the rest of the week.
A rolling system fixes both. There will be no easily determined "best time" to post, since there won't be a sudden and arbitrary wipe of all competition, and, by nature of the rolling system, every article will receive exactly 30 days (or whatever duration) of promotion. People will post whenever their drafts are ready since the competition is unpredictable (and thus more fair) and the amount of promotion remains constant for all posters.
I really hope we change to a rolling system. I'm bored to death with what we have right now. I don't want to have to slog through 30 articles that get posted in one day then nothing for the rest of the month. I'd rather have one article a day. The content drought then sudden, explosive oversaturation isn't healthy for the site.
tl;dr: Top-Rated of the Week still allows for exploitation but a rolling system fixes the inherent issues in our current system.