Of course I don't think you're trolling! Everyone is entitled to their own opinion, and I didn't intend to make my comment about the drawback seem directed at you and/or snooty, forgive me.
I'll politely disagree with you again, however. Avatars tend to tank while soloing, and reducing what meager defense they have (even with a flat 50%+ reduction) would be a little much, considering that most of the Summoners I know or have known are soloers. The last thing I want to do is reduce my protector's defense.
Also, a Hasso-like ability wouldn't really fit what Summoner normally does, which is consume/maintain MP. It just makes a little more sense to make the drawback go around that. Bringing Avatar's Favor into the matter though, it reduces an Avatar's physical/magical prowess, so I suppose it wouldn't be an impossibility to implement, just unnecessary in my opinion.
Please don't add fuel to the fire. It is, honestly, irritating to sift through pointless arguments to read through forum threads.
Edit: About the "being complicated" thing, I didn't mean to program, I meant that adding additional perpetuation would be easier to deal with in the long run instead of suffering from an instant stat decrease for the entire duration. It would be less complicated for perpetuation because unless you plan for it (or merit it), it hurts you over time (outside of Abyssea).