It's a small world, fellow Canadian expat here from Toronto originally, and my wives parents were French Canadian from Montreal, we still have relatives up there that we visit when we can. I know the area and spent many summers at Severn Falls growing up (right near you) absolutely beautiful area. (I swear there's more Canadian expats here in Sarasota, Florida, than any other group). My story is I started out in Canada , 'way too cold', moved to Minneapolis, still too cold, then moved to Wisconsin/ Illinois border, ' still too cold', now I live in South Florida 'just right'.
Typically the rudder up line is supposed to stay taught, with no sagging, and whether the rudder is up or down it should snap all the way in every time, if not then it is catching someplace and snagging. It's actually two lines next to each other (one bungy and one rope tied together to make the tension, if they are hanging up anywhere (probably on the flotation foam inside the hull near the rod holders) then the line is allowed to sag, once the up line starts to sag and wander around inside the hull it gets tangled up in the rudder mechanism, and anything else that may be inside the hull (the main culprit for binding is usually the flotation foam inside the hull wandering around, (or a lost tennis shoe).
Other than that (lines and stuff getting caught up in the mechanisms) , the rudder control lines and rudder system in the TI is pretty rock solid. There are basically to lines, (both steering controls are attached to one of the lines) with very heavy line (1000 lb test), that should never give you problems. There is a return pulley up at the very front (about a foot or so in front of the forward steering control), I have had problems in the past with that pulley twisting the lines on themselves way up there near the front but that was on my first TI back in early 2010, and I think they have improved the design to prevent that from happening now.
Near the rearmost hatch there are a couple guides that hold the steering cables up and tight against the underside of the deck (on each side of the rear hatch (inside the hull), check to make sure the lines are not twisted into each other back there also. Make sure those lines stay in those guides (they get knocked loose from the guides sometimes when loading gear), this can affect steering, and also can cause water to come in the rudder guide tubes (If the tubes aren't strapped up against the underside of the deck, water can come in).
Actually I have a lot more trouble with the rudder down line on the right side of the boat, the down line is a double purchase (2/1 ratio) and there is a pulley just behind the front pull down lever that constantly gets spun around on itself tangling the down rope around itself until the down line just doesn't pull the rudder down any longer. You know this is happening when you release the rudder down line from the cleat and the line doesn't return into the hull . I have to untangle mine every few weeks. One of the results of this is you pull the line tight then cleat it thinking the rudder is tight down in the back of the boat. But if you go back and try and lift the rudder it is still loose, this makes the steering very difficult and hard to turn the rudder when the rudder is not down and locked tight. You actually have to pull that down line tighter than you would think, then cleat it in order for the rudder to operate easily.
Actually I often pull the rudder down and lock it, then just for piece of mind go back to the back of the boat and try to lift it (I guess I'm gun shy now).
Another thing that can cause steering issues is if the rudder steering lines are too tight, this puts strain on everything, Most of us have placed stainless washers under the screws back on the rudder (where you adjust the rudder lines), the washers give you more gripping surface, and also prevents shredding the rudder lines.
I suspect 9 out 10 of the rudder problems we have seen people complaining about really hard steering, are the result of them not cleating the rudder down strong enough, or not at all in some cases.
Hope this helps (sorry for the rambling)