^ I think at the end of the day Sega has is known for more then just their original in-house developers. It's more of a brand and there are a lot of things recognizable to the brand. When I think of Sega I usually think of very fast paced, very actiony, Very Arcady games that are unashamedly 'videogames' and don't pretend to be anything else. They'll have a big 'SCORE' in the top corner, LIVES in the bottom.Great things like that.
Of course this isn’t every Sega game but that’s my general idea of what makes Sega, Sega. Although the Treasure games aren't made by Sega they fit the bill of what it is to BE 'Sega'. I think the same thing goes for Bayonetta and Vanquish. Both are very fast, very actiony... often kind of cheesy and unashamed to be a videogame.
I think they fit the bill of 'Sega'. Of course there are games not made by Sega at all that I also think 'this is something i could imagine Sega making' and there are Sega games I could say 'This is something i could ONLY imagine Sega making.'
(NOTE: I've had a drink, currenly what I said makes sense to me... It may not actually make sense.)