A lot of research would have to be done to come to a conclusion, but the heads for each are quite different. The head of Resident Evil 5 was someone who took it up that game. Before that, he mainly worked on the Onimusha games as well as was Lost Planet titles. However, he announced a few years ago he wouldn't be leading future Resident Evil games.
The guy in head of Revelations is actually fresh blood. He just was a producer for Samurai Western and was a designer in RE5.
For 6, the director is the person who previously directed the two Resident Evil Outbreak games. He also helped plan Rival School almost 15 years ago. Apparently he has a big interest in directing,cutscene direction and motion capture, as well as game design... At least, he did all of those for both Outbreak games.
Interestingly, the producer for RE6 did a lot of the work on quite a few games, including Resident Evil REmake, Zero, and Code Veronica, as well as Dino Crisis 2 and, surprisingly, Killer7.
BH5 was led by Jun Takeuchi, who was an enemy designer for BH1 (1996) and motion designer for BH2. Co-producer was Masachika Kawata, who was a CG background designer for BH3 and the REmake, and produced the PS2 version of BH4. The staff was made up of a lot of people who worked on the first game, but Takeuchi was known for not being a very good leader and his ideas conflicted with everyone else a lot.
The producers of Revelations actually had the most clout over the game, apparently. It was produced by Masachika Kawata (who produced the Chronicles games beforehand, and was "producing" Operation Raccoon City at the same time), and assistant producer was Tsukasa Takenaka (honestly one of the better members of the BIOHAZARD Team, he worked on the background story for BH5 which was excellent).
The men in charge of BH6 are much more experienced and consistent with quality. The director is Eiichiro Sasaki (director of the Outbreaks), executive producer is Hiroyuki Kobayashi (was the producer for CODE:Veronica, REmake and BH4, and is also credited as "Support" for BH3 and "Promotional Producer" for BH0, and produced Degeneration and Damnation), and producer is Yoshiaki Hirabayashi (REmake motion capture, BH5 cinematics supervisor and script).
No word on who the writers or planners are yet. The lead planners for BH4 were Hiroshi Shibata (who directed the "Fog/Hookman" version), Kouji Kakae and Shigenori Nishikawa. The latter two were the main planners on REmake, while only Kakae worked on BH5.
I'm not a fan of Kawata. Barring Revelations (which Takenaka apparently had more involvement with), the man has presented nothing but mediocrity or failure.
EDIT: The horror in BH6 is sounding promising.
http://kotaku.com/5900649/in-resident-evil-6-even-the-zombies-have-guns