I really agree about Marcus' involvement on eviction / finale nights. I'm tired of him screaming into the House. Take it back to the days when a BB voice would do the announcement, please! This isn't a dig at Marcus, he's fine when he's reigned in, but he never is when doing these announcements. Also, even if he was less OTT for them, I still wouldn't love it. It really makes little sense for anyone other than BB to do it.
Compare with the typical C4 eviction (from around 2:17
https://www.youtube.com/watch?v=G6chF4bF4QI ).
Other changes I'd make that hark back to earlier series:
* Having the housemates all gather in the living area during nominations.
* Go back to the format of the C4 end-of-series montage. They'd show events on a week by week basis (ending each with the eviction and a fade out), and they were accompanied by a nostalgic, emotional song. Nowadays, we usually get a random mish-mash of events (with tacky on-screen subtitles, "LOVE!", "ARGUMENTS!"), and different songs, usually dance music. BB14 remedied this to an extent, it felt much more like the old style ones, but from what I remember CBB13 returned to C5 form.
C4's montages used to always make me feel emotional about the series ending. This is the sort of thing I mean:
http://www.youtube.com/watch?v=5C3lkBs7Keg