Every boat has its pros and cons - the all around perfect boat hasn't been built and isn't likely to ever be. And each boat has its operational "sweet spot" (The WindRider probably having the widest range, being able to handle 5MPH to 50MPH winds and rolling seas, but that's another story.) The AI and TI's are more than just sailboats. And for that reason persons wanting just a sailboat, may not be overly impressed. Now if you're fishing, snorkling, camping, etc., then they're tough to beat.
The Weta was never marketed as an H18 beater - nowhere on their website does it claim to be. Heck, it's a 14 footer with only 210 sq. ft. of sail (that's all three sails). The H18 is an 18 footer with 250 sq. ft. of sail, and a mast that reaches 4 or 5 feet higher than the Weta. If you're on an H18 and can't beat a Weta around a regatta course, you're not much of a sailor.
The Weta was designed the way it was for a reason. They wanted it to be trailerable, easy to rig by one person including stepping the mast (I can do it in 15 minutes). They say it's easy, and it is mostly, but can get very, very busy when single handed in good wind with all sails in use. You have to move from out on the tramp, drop into the hull trough, then climb back up and out on the other tramp. It's a lot easier to swap sides in a cat. The Weta isn't hard to capsize - the ama floats are low volume. But with a little care and smart selection it's pretty good about staying upright. In effect, it's pretty much what the company says it is. Tacks in an instant. And it is fast, very fast, for a 14 footer - it's nothing to get it up to 14 or 15MPH and we know they'll do 18-19 in the right conditions with a good sailor. So if you want to compare performance of the Weta to something else, choose a competitor that is roughly the same length with the same amount of sail, something like the H14. Do that and suddenly the Weta becomes a really great boat. I just think the idea that the Weta is somehow lacking because it won't run past a much larger and more powerful boat like the H18 is a bit off the wall. That's like saying the H16 is a dud because it won't stay with an H18.
What I'd like to see, and I'd like to see Hobie do it, is come out with a performance trimaran in something along the lines of a 16 or 17 footer. Even in a rotomolded type of thing. Affordable. I had high hopes for something like the proposed Motive 15R, but it appears that one isn't going to happen. So, there exists a real gap in the market, with the Weta holding down the small "pocket" trimaran end of things, nothing in the middle, and then the big, costly tris in the 22+ foot range. There's an opportunity here for somebody, I think.