Welcome to the intertubes, II! That kind of experience is not uncommon for women - I think it's a bit less likely for men to experience hose-beast-ness but it certainly happens.
And, yeah, length of message can be an early indicator of sanity and/or creep levels. Too short indicates someone who isn't really trying, is boring, or finds you boring but wants to fuck anyway - or only wants to fuck.
A too long message can be verbal diarrhea. They talk about everything under the sun, which may or may not be related to one's profile. This is offputting for me because it means - they didn't read my profile to figure out what I might like, or they can't figure out how to approach me in a non-creepy, non-desperate fashion. Either is bad. Oh, and they don't know how to edit themselves. I'm big on that and find the lack of editing a turn-off.