Well, my understanding is that there's a difference between sexual objectification and idealization. Sexual objectification is "this character has been designed this way for you, the consumer, to derive satisfaction from ogling" and idealization is "this character is awesome, look at how awesome they are, you want to be this character". Female characters in games are largely subjected to the former and male ones to the latter. (Not that idealization of male characters doesn't contribute to body issues or that male characters can't be sexually objectified, but you know, in general it's like this.)
[possibly talking out of my ass but fuck it, nothing ventured nothing gained]
Samus in a catsuit is probably the former. She is put in a catsuit because "hey look, boobs! you like boobs, don't you? let's accent this woman's boobs because boobs are hot!". Kratos is topless to express a sense of power. Look at Kratos, the design decision says. Kratos is powerful. Kratos is the hero. Kratos is in control, the muscles say so.
[/possibly talking out of my ass but fuck it, nothing ventured nothing gained]
Tangent, but there's also a difference between "this character dresses/acts sexily because they're confident in their sexuality/it's in-character for them/etc." and "this character is sexualized to titillate the viewer". Often, jackasses think the former is happening when really it's the latter.
