What do you mean?
A logo is your BRAND's SIGNATURE, your face in the marketplace. By that it is a BIG thing. A logo should attempt to be immortal and o expense should be spared when selecting , buying or designing a logo. Once you have developed your logo you should change it willy nilly either (in other words all expenses on a logo are up front... cheap/qiuck logs are a mistake)
creativity is right, but creativity is subjective. personally I find the best logo one ones where the execution/rendering makes the the client say "i could have DRAWN that!" but the idea is so elegant s/he also says " wow, it's whtat I wanted to say but I never saw it that way "
If you mean physically. Well generally, yes, logos should be demure. Like I said they re your face and your signature. it's important that a letter has a signature, but you seldom write your signature bigger than the message in the letter do you? essentially that should be the approach when handling brand marks.
As long as we are on the subject of 'physical size' a logo design should allow it to not only convey your message but to remain essentially clear and crisp whether it's reduced to the 1/2 size of a postage stamp or enlarged to the size of a skyscraper.