WARNING: The following article contains spoilers for Avengers #50, on sale now.
Comparing the strengths and weaknesses of superheroes has always been a favorite fan past time and opportunity for intense debate. In Avengers #50 (by Jason Aaron, Aaron Kuder, Carlos Pacheco, Rafael Fonteriz, Ed McGuinness, Javier Garron, Alex Sinclair, David Curiel, Matt Hollingsworth, Rachelle Rosenberg, VC's Cory Petit), Power Princess and Doctor Spectrum -- both Marvel iterations of Wonder Woman and Green Lantern -- get the chance to settle who would win in a fight between the two.
The Aaron / Kuder creative team depicts Power Princess graphically smashing a hole through Doctor Spectrum's chest to grab his power crystal, and the Green Lantern stand-in doesn't even stand a chance. It shows that in a hypothetical Wonder Woman vs. Green Lantern battle, the Amazon could win easily. However, there are some storytelling nuances that deserve further explanation and counter why it might not be so easy to for Wonder Woman to sneak up on and ultimately defeat Green Lantern.
For starters, Doctor Spectrum and Power Princess are faithful parodies of their DC counterparts but they are not exact copies of their inspirations. For example, Doctor Spectrum's powers are ostensibly akin to a typical member of the Green Lantern Corps. However, the Marvel version, as depicted by Aaron and Kuder, is fueled by an entirely different power source that may even come with different rules. Power Princess' simple sneak attack suggests that while the crystal does provide offensive capabilities, it is severely lacking in defensive power.
In contrast, a typical Green Lantern ring from the DC universe naturally possess protective auras. These defensive barriers shield their wielders from the vacuum of space or whatever dangerous environments they find themselves in. It even makes them capable of going toe-to-toe with beings that would normally kill them in one blow. In Avengers #50, Power Princess's killing blow to Doctor Spectrum would have been impossible according to the rules established in the DC Universe. This suggests that Doctor Spectrum's crystal is definitively inferior to a Green Lantern power ring. It does not change the overall premise of Wonder Woman's capability of killing any Lantern, especially if she puts her mind into.
There are also questions about how the defensive capabilities of the rings and the crystal work in both comic book universes. The Green Lantern rings provide passive protection at all times but can also provide extra layers of defense with enough individual willpower from the ringbearer. These defensive shields are capable of withstanding massive amounts of punishment. At the same time, it is not impossible to penetrate a ring's defensive mechanisms. In Geoff Johns' run New 52 Justice League, Batman was able to slip Hal Jordan's ring off his finger without him noticing. Lantern defenses have always been capable of identifying threats but they are also dependent on the self-awareness of its user. At the time, Hal did not register Batman as a true threat, owing to the Caped Crusader's lack of superpowers.
The above example from a DC storyline could be a rationale for the Power Princess conundrum in Avengers #50. If this principle crosses over and is applied to Doctor Spectrum, then it is possible the crystal did not protect him. The crystal did not register Power Princess as a threat to Doctor Spectrum. They were ostensibly on the same team. Therefore, Doctor Spectrum would have had no reason to consider Power Princess an enemy before it was too late. Regardless of the true reason though, Power Princess' actions confirmed that Wonder Woman could kill any Green Lantern.