I'm not really in the picture what new shows there will be - it typically takes some time until they're available on FreeTV here in Germany.
So, looking over what was mentioned in this thread:
Gotham - should be cool
Doctor Who - not my cup of tea
Arrow s3 - meh. I'll probably keep watching it, but it doesn't excite me
Flash - could be interesting
SHIELD 2 - my expectations are low, considering what I read about it so far
Walking Dead - can't wait! the last season was terrific!
Big Bang Theory - mhm, I'm not a big fun of comedies, this is one of the few I watch from time to time
Downton Abbey - i was a bit disappointed about the last season, but overall I still think it's great
Constantine - see Flash: could be interesting
Star Wars Rebels - yuck!
Agent Carter - no idea
Sleepy Hollow - first season was terribad, so, nope
Forever - huh, hadn't heard about this one before, sounds potentially interesting
Selfie - probably as stupid as its title
Gracepoint - why a remake? Apart from that, it could be good.
Gallavant - umm, no, I guess
I have no idea when they'll be shown here, but apart from 'Walking Dead' and 'Downton Abbey', I'm most looking forward to
- The Americans s2
- House of Cards s2 & 3 (s2 starting next week, yay!)
- Game of Thrones s4+
- True Detective