MGS1 had the balance between gameplay and cinematics. You play for five minutes, you watch a few minutes. You play five minutes, you watch a minute. You fight a boss, you watch a few minutes. You play five minutes, you watch a few.
It was a good balance. MGS2 was nothing but long, drawn-out CODEC conversations with people standing right beside you. And if you skip all of those and the cinematic scenes, the game itself was only about two hours long (legit - I've finished MGS2 in two hours...the Plant, anyway. Tack on an extra half hour for the entire thing).
MGS3 was a little better, but so little happened between meeting Eva and reaching Groznyj Grad that the whole middle of the game, at least to me, felt very dull and boring. Just a lot of "Go here, get this, Then bring it back here and do that. Now go see him, and then head there." I don't think it was as painful as MGS2, but still, I wish the middle of the game was as intriguing as the start and end.
MGS4 was nothing but story. It wasn't particularly bad (until that FINAL scene), but there was just too little game. It suffered from the MGS2 syndrome, except it overdid it on the cinematics instead of the CODEC scenes, and there was far too little gameplay. And what little gameplay there was basically boiled down to either slowly crawling everywhere if you wanted to stay stealth (which took a LOOOONG time), or just CoD-style runnin' & gunnin' your way to the end (which took barely any time at all).
If I had to choose between MGS3 or MGS2 & 4's style of pacing, I'd pick 3 as well. But I'd rather go with the MG2:SS & MGS1 style over 3.