GPS isn't going to get me to upgrade. Better performance is what I'm after. The watch OS 3 should help with that, but it needs more RAM to keep things going in the background, more storage space for music and photos, and better graphics performance so it's not so laggy when scrolling or playing a simple game like Pong that kills time. LTE would be neat, but all it really needs is 3G, as that's about as fast as it can connect to the iPhone anyway, and 3G chips in tiny packages today should be much more power efficient.
Something that people don't think about is if the Apple Watch is running on LTE, then the apps are no longer loading off the iPhone and have to be completely stored on the Watch. That means much better performance and storage is needed, which can limit battery life, especially when factoring in LTE, and even more so with a GPS. I don't think the hardware is mature enough to handle that, but maybe in another 18 months if they stick to that cycle. I think that's a good cycle for the Watch, and makes every-other-year upgrades at 3 years more sustainable for users. I'm willing to upgrade my Watch every 3 years, especially if they offer a band-less version for like $50 cheaper that works with all my existing bands.
One thing I know for sure is that Apple must be working on it. That $129 up-charge for cellular is likely high on their priority list for AW3. I don't think the Watch needs to be like the iPhone, at least not for a long time and maybe not until they can make big display bands that wrap around your wrist that are comfortable and stylish and work well. But having cellular on-board would still be welcome for loading the little bits of data that Apple Watch apps are good at displaying. I'm hoping that a data plan for something like that would be a simple $5/mo charge, as it wouldn't use much data. Anything over $10/mo would be a fail IMO. And I think 3G would be a good fit. I think Verizon said they weren't going to keep supporting their 3G network, but I think I read somewhere that they decided to keep it going for the IoT (Internet of Things) initiative going on right now. Maybe someone here on the forums told me that, as I've been sleep deprived lately with a new baby. IDK.