First, WB rarely ever deviates from ranking when seeding the women.
They won't drop an ex-champ from #4 to #5, even for another ex-champ.
I think it depends on who would drop from #4 to #5. Jenn, Venus, Martina are 1, 2, 3 now. Martina is an ex-champ, Venus is defending champ, Jenn amde the semis last year and is defending OZ champ. None of them are getting seeded below their ranking.
Monica - Still one of the biggest names in the sport. If she up to #4, (I admit this is unlikely) they won't drop her back.
Serena - Decision of the marketing department. Probably safe because moving her to #5 makes the possibility of Serena vs Venus in the QF. Hypewise, you want that match later. But if an uninspired Wild Thing is going to show up vs Venus, then switching Lindsay for Serena is a good idea.
Justine made the final last year. If she's #4, they'l leave her.
Anyone else might get smacked, especially if Lindsay wins a grass tuneup.
Wimbledon no longer seeds subjectively, remember? They now use a system that raises players based on their past 5 years Grasscourt results. Expect this system to make Venus the #1 seed, unless she is far back in points, which is unlikely. The other players who are likely to see their seedings go higher are Lindsay and Justine.