THUNDER AND LIGHTNING: Storm can use Energy Explosion. If both Storm and all targets of her ranged attack are outdoors, she can use Precision Strike.

With Precision Strike only working on single target attacks now under 2017 rules, how does that affect the use of Thunder and Lightning, above? Should it still work as originally intended, or is there a new wrinkle to it all?

There's at least one piece that's been erratad to allow multi-target precision, but in the end, golden age decisions like this are really up to the judge.

That figure did not recieve any errata so technically the Precision Strike would only work if you single-targetted.

Obviously a local judge can make their own intent ruling but there are Golden Age figures with similar powers that did receive errata, like OP Dormammu:
http://win.wizkids.com/bb/viewtopic.php?f=29&t=12737

As written she could use either Precision Strike or Energy Explosion, only way she could combine them is if she is only using Energy Explosion on a single target.

Storm would only be able to use PS against one target. She was legal for quite a while after the rules change, and didn't receive errata. There are plenty of figures that have both PS and EE, she works the same way as the rest of them, just like before the rules change.

There were only two figures that received this type of errata, I believe, Electro and Dormammu. Both have special powers that give them PS specifically for the purpose of targeting multiple characters. Storm, and other characters with EE/PS, just have standard powers that were specifically changed to not work together any longer.