Well, you maybe right, but trust me - I have played pretty good youth competition where (unfortunately) many teams played zone. Thus I know maybe more about attacking against it then defending. We've spent much of your practice playing and improving our counter-zone attack and I know where are the weakest areas of zones. By all means, it depends on how good your attack and good the defense is, but for instance our 4-1 zone offense could beat every 3-2 zone.
The problem with 3-2 defending the corner is actually not when the player has the ball and thinks what to do next (you are right that if it is played slowly he has only a limited number of possibilites to do) - but there are very easy ways to get him open there and then he has nice immediate open shot because his wing defender is on defending the wing on his side and the big man is far away from him. Trust me, shooting from outside is the easiest way how to beat zone defense (not the best!).
2-3 zone in the corner - you maybe right again, but that's what the coach is for and when he knows that his big man is not fast enough to be there on time, he must choose other defense or other defender. But even if there is the best driver against him, there is not much he could do, because he is right in the corner (usually being double-teamed immediatelly) so his options are to shoot or to pass. It is very hard to penetrate on the baseline because there is usually even a bigger man waiting inside the key.
Yeah, zone is now a more complete & complex defense but only when it is being played well. But as my former coach says "zone is a shame of basketball" and I am with him. :-D