Thanks all for the replies.
Probably the single most pertinent thing I'm looking for in newer models is increased range in the Model 3. Little additions like heatsinks are certainly great and welcomed, and I expect them to continue to fix types of issues like panel gaps and other structural abnormalities that are getting fine-tuned year to year since the Model 3 is still so new.
But I want primarily more range. It's a bit of a shame since they can easily put more battery cells in a Model 3 (if they're making a Model S with 520 miles, and have a Model S with 412 miles, there's no reason they can't make an even longer range model 3). It's possible that maybe they add more battery cells mid way through this year, but most likely they will increase the range with new model years, perhaps.
As soon as the tax credit get finalized, I will probably just end up making the purchase anyways, assuming I have to get it within the 200k-600k # of vehicles sold. Though if Biden's $10k credit comes through, perhaps the 600k limit won't be a thing, and I'd rather just wait a few extra months if needed to get something with more range and another novel feature (like in the heatsink category).