Ok, I feel a big rambling post coming.... I have the LD12, LD22 and PD32. I agree the LD22 is a little long. Too long to wear on the belt and it gets itself wedged in the pocket in a bad way too. I mainly use it for a 'house light'. Something to sit on the coffee table in case my wife or daughter needs a light. I am trying not to leave Li-ion lights around the house for general use (and abuse).
The pd32 is noticeably brighter on max. Similar beam to the LD22, but brighter spill and brighter hotspot and a bit more throw. "Tunnel vision" does not come to mind, its a decent mixed beam. Its more impressive than the LD22, but it might come down to what you need to illuminate to say if its truly more useful in your situation.
Performance will not be any better on li-ion, just cheaper after the initial high investment. Use two primaries or one 18670 or 17650. DO NOT USE TWO RCR123 (rechargeable), too much voltage for the PD32.
All in all, I like the PD32 a lot. I got it for special occasion EDC, like when I expect to be needing a brighter light than my LD12 after dark. I mainly use my light for daytime projects. However, I'm finding the extra brightness is great when working on equipment outside in the sun too so I have been carrying it almost everyday now.
Also consider other possibilities. If you like the side button, the PD22 might be good. Pretty much the same output as the LD22 and way smaller. No rechargeable support. If you are only flashing your light a for a few seconds here and there during the day, a single 123 can last you for several months. Also take a look at the Quarks, many options. The single cells will get you similar output in a smaller size with more battery options. Two cells with xm-l emitter will get you a brighter light.
So back to the PD32, nice light, quite pocketable in my cargo shorts. I'm not sure I would love it on primaries though. Most of my use is quick flashes here and there, which would be fine on primaries, but some projects turn into needing light for a steady hour or so and that would kill me to run down primaries like that. Think about how you will use your light. A good li-ion setup could cost you ~$70 to get started, although you can find cheaper stuff. I have the Pila IBC. If you don't use your light a lot, it may take years to recover your investment. If you go for the PD32 or another 2x123, try a few primaries and see how it goes before diving into li-ion. If you keep your LD22, consider eneloops.
Good Luck.