An intangible reason ("had more heart") makes a player better? More heart doesn't excuse Ray Allen clearly outplaying Iverson in the '01 ECF:
Allen: 27.1 PPG, 3.3 RPG, 5.4 APG, .9 SPG, 2.7 TOPG, 46.8% FG%, 50.9% 3PT%, 96.8% FT%
Iverson: 30.5 PPG, 4.8 RPG, 6.8 APG, 2.2 SPG, 2.7 TOPG, 34.4% FG%, 33.3% 3PT, 78.2% FT%
Keep in mind AI took 40 more shots than Allen to average three more points. Allen was noticeably better on both ends (AI played his usual gambling defense) and Ray helped his offense flow quite well (considering how good Philly's team defense was). MIL's efficiency was superior but their volume wasn't.
I'm sure this'll be ignored but AI had an ORTG that was almost 30 points lower than Ray Allen. I understand the disparity in offensive talent even between Allen's Bucks and Iverson's Sixers but 97 vs 123 can't be ignored.
Arguably the biggest reason Philly won is because Dikembe Mutombo came outta nowhere and averaged near 17-16 with 3 blocks and had a higher average game score than AI (meaning by this stat that Mutombo was the most overall impactful player on the Sixers' roster. It's flawed but Mutombo stepped up more than people realized). Was well-known that Milwaukee had a poor front line and Mutombo ate Ervin Johnson-Tim Thomas-Scott Williams alive on the offensive glass (6.4 OREB per game). You guys wanna tell me about more heart without looking at what AI actually did?
And yeah I've watched both Curry and AI extensively (pertaining to OP's topic). AI was never a pure distributor and we saw that in Detroit after the Billups trade when AI played more point, AI wasn't a natural fit at PG and they fell off. You can take the guy with a bigger cultural influence (great thing in itself but topic is about better player) and more influential narratives, and AI does still have a case, but by looking at both Curry at his peak as of now definitely has a case over Iverson. People acted like it wasn't close, which isn't really true.