Yes, I can shed light on this subject for you. My commissioner set a transaction limit of 25 moves this year. The reason was simple (and the God-honest truth straight from his mouth): He didn't want me snatching up all the usable players off the wire before everyone else could.
I'd read up on that trade rule you speak of because in my league there is no limit to the amount of trading you do, but it still counts against your "transactions" count.
He's got a point about the "sanctity" thing, but I wouldn't have worded it that way...just sounds freaky! It makes your draft more important since you can't just be switching between each "flavor of the week" off and on the whole year.
Actually, having 25 moves per year isn't bad; it's almost two a week, so you can still switch defenses every week and/or switch off for bye players and get those gems off the wire.