I don't really see the pacing issues since it takes about 15-30 minutes to figure out a route through the guards unless you abuse tranqs but even then you don't have infinite ammo so you have to save your tranqs and find tranq ammo and the like. Once you get past those, the cutscenes are generally ~5-15 mins max unless you're in MGS4 which is OH GOD WHYYYYYYY in terms of cutscenes (Act 5 before the fist fight. WHYYYYY).
Then you haven't played MGS2 and MGS3 in a long time
MGS2 has at least 2-4 hours of cutscenes, 1-2 hours of codec talk. MGS3 has about 2-4 hours of cutscenes with a lot less codec talk. The beginning of The Plant chapter is brutal, you take a few steps before the colonel forces a interruption or a cutscene starts.
Don't know what "abusing tranqs" means, unless you want to handicap yourself on purpose on lower difficulties, it doesn't make sense to not use the tranq pistol. Not using the tranq pistol in MGS2 on European Extreme means you won't beat the game, or rather, you're going to be choking a lot of dudes.
MGS as a franchise is also really easy unless you play on harder difficulties, it shouldn't take 15 minutes to clear any area in any MGS game. MGS1 can be beat under 3 hours skipping cutscenes. MGS2 can be beat under 3 hours skipping cutscenes, MGS3 can be beat under five hours skipping cutscenes.
MGS3 also has the Virtuous mission when it comes to pacing, which is one hour of story stuff and exposition, with 10 minutes of gameplay.
