First and foremost: There is no worry of stretched ignition switch wiring on a tilt column. The switch is actually located down near the pedals, atop the column, and is actuated by a linkage rod running the length of the column from the lock mechanism to it. The rod runs parallel to the one for your dimmer switch, which is right next to the ignition switch on the column (see picture below). You're in no danger of shorts, fires, or other electrical maladies whatsoever. I wanted to put your mind at ease about that.
The problem can lie in a couple of areas:
First and foremost, the switch itself could be worn. The metal linkage rod from the lock mechanism down to the actual switch is anchored in plastic inside the actual switch. If that plastic is worn into an oval, the rod may not be able to fully engage the start position. This is the least-expensive, easiest possibility to correct.
Another problem can be with the upper sleeve (the outer, visible jacket of the column where the lock cylinder rides) being worn. This problem is most common among teenage girls, janitors, maintenance guys, and building superintendents that have very heavy keychains. The lock cylinder rides directly on the pot-metal jacket casting and wears it away. Slop develops in the bore for the lock cylinder. The slot in the back of the cylinder doesn't engage the mechanism correctly, wears, and again the rod can't move the switch fully through its range, "start" being the furthest position. The test for this is to firmly grasp the "wings" on the lock cylinder and wiggle it fore and aft inline with the centerline of the sleeve. It should not have more than maybe 1/16" of play, if that much. If you have a ton of slop, it might actually kick the starter for a second while you're doing this. Since the column is, ahem, a GM part (sorry guys) the aftermarket Standard Motor Products sleeve, part #US165L, might fit and function properly, but I can't swear as to its appearance being correct. The lock cylinder may well need replacement as well; look at the slot on the opposite end from the key.
Lastly, your tilt mechanism might just plain be too sloppy. I've never actually tried to fix one so I can't describe the procedure or the parts required; I can't even say if it's something that's feasible. Most of my cars were solid columns and I've never had the problem myself but have dealt with it on more than one GM product. Personally, I never went beyond changing the switch itself and generally people just lightened their keychains and lived with it if the switch didn't correct it.