Sorry to hear about your experience with your i series Kayak.
(I own a 10 year old Innova 'Sunny' that has never let us down.)
I have a Dune (Ivory) 2011 AI. My dealer made sure I got the larger rudder.
I'm still using my old 'Twist and Stow' rudder that the boat came with.
Why, as Matt Miller said, if you know how to run the rigging method on the 'old rudder' you hopefully will not need to upgrade. (I'm also slightly conservative when it comes to switching out gear...("Don't fix it unless it is really broken")
Yes, a few times I lost partial control, but a lot had to do with lack of tension on the cockpit mounted rudder downhaul lock in 15-20 knot winds. Remember, this is a boat that loves balance:
The rudder Uphaul line/downhaul line lock use a bungy to keep you from snapping the rudder pin if you hit hard on solid ground.
My solution with the present Twist and Stow Rudder is to take all the stretch out of the bungy by pulling as hard as I can before locking down the rudder downhaul in the camcleat provided. (remember also not to use the same area every time of the camlock teeth so they stay sharp to hold the thin lines used on the downhaul rudder system. This also demands a certain 'flight plan' as you get close to shore.
1) reef the main partially (slow down) if the wind is onshore
2) read the water under your keel (if you can see bottom, time to pull up the daggerboard, if you haven't already...)
3) get your rudder stowed.
4) Put your Mirage Drive into 'neutral' and lock it down with the bungy so the blades are tucked close to the hull)
5) Furl your sail completely and wait until your speed is 'Dead Slow'.
6) jump out and stabilize your craft (whatever it takes, as long as you will be safe doing so)
Every sailing vessel has their own steering characteristics. Remember you are using a simple little arm to control the steering.
Years ago I actually snapped a laminated Oak Rudder on a Catalina 27'. Yup it did have a bit of rot due to a few places where the varnish got chipped off, yet the weather helm was so severe that a 5 foot tiller snapped off at the fitting. (I pushed the boat too hard by over tensioning the Gennaker, Jib and Main)
Hopefully you will never have to try to steer your vessel into a very busy channel hanging onto the stump of a tiller that should never have broken. (Thank Neptune for Outboard motors with their own tiller)
Another thought, by 'choking' a sail (over tensioning the main sheet) will cause more weather helm. Consider letting out your sail a bit and see if that takes the strain off your rudder control?