That's exactly what I've been doing, although I'm not even halfway through GoW '18.
Honestly? Not sure if it's because I never played it when it originally released, but GoW 3 felt pretty lame.
The story is downright terrible, the cutscenes are mostly low effort with awful animations, dialogue and voice acting.
The game can sometimes look pretty good, but to get to a nice looking place you go through a lot of boring corridors and rooms, filled with annoying puzzles that aren't even stimulating your brain and just waste your time. Out of all the boss fights, I probably liked just the first one because the sense of scale on Gaia was great, likewise with Cronus.
All in all, seems kind of mind boggling how this was such a critically acclaimed game when it gives you a completely average 8-10 hour experience with almost nothing going for it. I'd probably rank it 6/10 at best, but again, not sure how I'd think of it had I actually played it in 2009. I just know that if I compare it to other big titles at the time, like Gears of War 2 / Resident Evil 5 / RDR it's way worse in every way and I don't think it's because of rose tinted glasses.
Oh well, luckily GoW '18 is correcting that and I'm enjoying it a lot more.