I also dislike the requirements for the same reason I disliked requirements for feats and prestige class in 3.x - they make you plan your character out in advance. I'd like for people to be able to spontaneously multiclass their character. Maybe something happens to your rogue during the story that he finds religion and decides to become a cleric. It would be, IMO, unfortunate if you couldn't do that just because you didn't have the foresight when you made the character to put enough points into Wisdom.
The only way you could do that is make it so that abilities had no synergy with classes or feats at all. If you could multiclass into cleric reasonably regardless of your wisdom, it implies not only that there is no perquisite for clerics to have wisdom but that clerics gain no particular benefit from wisdom at all. I'm not sure I'd want to go that direction, because I suspect where it would end up is with everyone having 18 str or 18 dex regardless of class.
I started in 1e, and so when I adopted 3e for a number of reasons I established ability minimums for classes. For the most part, they are very weak - you have to have at least 7 str and 7 dex to be a hunter, for example. I also established higher prerequisites for multiclassing, primarily to insure that any multiclassing would create heavy multi-attribute dependency (because nothing with MAD is broken) and that there was a practical limit to the number of classes you could dip*. That was motivated by the fact that most classes were front loaded and I could foresee problems with dipping classes. I personally feel these decisions were vindicated by what 3.X became, though obviously, if you like where 3.X ended up with everyone having 3-6 classes and often multiple prestige classes you aren't going to be too happy with the restrictions I put in place.
But if your complaint is about planning characters out too much from the start, there is certainly no evidence that largely unrestricted multiclassing encouraged players to not plan their characters out in detail from the start.
*It's still pretty low. To give you the idea, a multiclass Fanatic/Fighter/Explorer/Hunter would need a 15 Str, 13 Dex, and 13 Con - still reasonable and likely in a martial build. But a multiclass Fanatic/Fighter/Explorer/Hunter/Sorcerer needs a 17 Str, 15 Dex, 15 Con, and 18 Chr. That isn't really practical. Generally 2-3 classes are pretty easy to put together under my rules.