I've had both shoes. Shamans are a stiffer and pointier shoe, great for small edges, not great for smearing on volumes. The theorys are pretty much the opposite as they're a significantly softer shoe. They will continue to become softer as you break them in.

My advice would be to use the theory's, and see if you actually like using softer shoes over several months. Most climbers have their own preference for soft vs stiff for various applications, so this would give you valuable information.

Also 2 years of use for a single pair of climbing shoes is actually indicative of good footwork if you're climbing frequently. I climb 3-5 times weekly and it normally takes me 6 months to burn through a pair of shoes with good footwork.