I took the opposite route ... I have had my kneez in the breez since 2010, and currently own a 2016 Gold Wing. I bought a used '15 STS SM5 kinda on a spur of the moment decision for a good price. I bought because it is completely the opposite of the GW, which I wanted ... diversity is the spice of life ... Gold Wing has navigation, Bluetooth, tons of storage, low revving torque monster six cylinder throttled by a cable, with an upright but relaxed seating position while the STS is a high revving, electronic throttle, with no infotainment system three-wheeler. Can't get more different.
I like them both, as I suspected I would when I bought the Spyder. As for your question about bikes, it is never too late to do anything because there are so many different bikes and options to accommodate whatever you need that bike to do for you, to tear it up in how ever define that phrase yourself. Ride is different in that the Spyder rides better - more tires, wheels and suspension to absorb bumps and distribute that energy through the chassis - a two wheeler may surprise you in the area of comfort vs. three wheels. Handing is .. well ... different. Riding a two-wheeler is far more technical in my opinion, but once mastered, more capable and far more natural than the Spyder (though BRP has it down pretty good). However, the thing I notice most about 2 vs 3 wheels is that I feel safer on 3. The stability factor ... and accounting for that in any maneuver you need to make on two wheels ... is not in the mix with your Spyder. This is as simple as not having to think about downshifting and which brake to transition to at what speed, and what foot to put down at a stop, or both or as complicated as regulating the pressure on the brake in an emergency stopping situation. For the record, I would highly recommend buying a bike with ABS.
Good luck!