...I suspect where most go wrong with Hobie mirage kayaks is for some strange reason they try to pull their mirage drives out when sailing or trying to sail, this defeats the purpose of the whole design. The thing is not a sunfish or a laser and shouldn't be treated as such. It's a mirage drive pedal boat, not a pure sailboat (never will be).
I personally have not sailed an AI in kayak mode, but have sailed my TI in kayak mode and found the mirage drive gives me sufficient skeg to sail upwind with a smaller sail (my kayak sail is a 33 sq ft wing sail for my TI). I always found that not using the mirage (that's why it's there) kind of defeats the purpose of owning a mirage kayak (might as well just get a sunfish).
Of course all this is just my opinion.
I'm sure I'm not agreeing with what you are saying.
I'm wondering whether the fumes from your twin outboards have clouded your judgement?
To suggest that 'removing the drives is wrong' and 'strange' is an ill-informed comment. It's obvious you have never sailed the Adventure otherwise I'm sure you would come to a different conclusion.
You seem to be hooked on 'motor' sailing, either with the outboards or just the Miragedrive, but the Adventure can be very successful in 'pure' sailing where it is just the wind that gets you from A to B.
In the right conditions (10+ knot winds) the Adventure with the standard Hobie sail and daggerboard makes a great sailing boat that can sail very well without the Miragedrive.
Speeds of around 4-6 knots are easily possible in 10-15 knot winds ,depending on surface conditions. According to my GPS I have hit just under 7 knots at times and have no trouble averaging around 4-5 knots ...which is faster than I can pedal/paddle. The trouble with the standard sail is that the mast can get a severe wobble at wind speeds of +12 knots and the sail needs to be furled. As a guide I generally furl to the tell tales at 15 knots and to the 'H' in Hobie at 20 knots. At 25 knots I furl to the 'I'. The Adventure is capable of higher speeds if the mast were stayed but it's difficult to stay the mast and keep the furling. Possible I know (I'm well aware of your excellent mast topper) but I like to keep it simple.
BTW-The Daggerboard is far superior to the Miragedrive in upwind sailing and adds stability on other sailing points, especially downwind. That's why I'm so disappointed that Hobie have decided to drop the Db slot!
PS: I agree with all that Diver, Stobbo and Simon have posted.