Actually as both GM and player, I like actions to have meaningful consequences, both negative and positive- while i'm not sneering down over my glasses at your play-style, its certainly not one I enjoy.
Even in Kingmaker, a delay on my players part cost them a pretty brutal attack on their capital. An attack which I fully rolled out with their NPC's defending the castle walls and in which major allies died. If the NPC's hadn't been so successful in defending it for so long, the place would have been sacked by the time my PC's arrived back. I ran the mass combat out in the open for my players to read as they raced home, right up until the last mass combat round (to preserve a little suspense).
If your playstyle involves there never truly being an incentive to hurry or knowing OOC that you won't be 'too late' for anything, of course the advantage goes to wizards and their ilk...
Even in Paizo AP's, I have my villains be pro-active. They aren't simply sat in a dungeon room, waiting to be killed off, waiting to start their ritual just as the PC's burst in.
Now that is simply my preferred playstyle; but I can tell you that the gap between Wizards and the other classes does not seem nearly as vast as you imply it is in such a playstyle. I often do not even see a disparity until 10th level +, due to a variety of reasons I am sure. Here are a few i'm fairly sure about-
1. Reactive world/playstyle and a sense of player urgency. It becomes fairly clear in my games that if your going to try and clear a dungeon or enemy stronghold bit by bit, novaing every encounter, that bad things are going to happen. This isn't just limited to counterattacks or reinforcements.
2. Intelligent tactics. A wizard has a very mighty toolbox. But there are counters to their spells and encounters do not occur on their terms in my games nearly as much as seems to be implied. Illusion magic in particular can make a wizard blow a significant portion of his payload on a minor threat and readied actions to shoot the spellcaster as he casts remain significant as long as the damage remains reasonably competitive.
3. Perception checks. I mean, seriously. The DC is not particularly high to hear your allies being slaughtered through the next door, or hear the wizard insisting everyone waits while he casts an endless series of buffs on himself.
Adequately prepared and armed with foreknowledge, there is no denying the Wizard in my games is always a force to be reckoned with; the most potent force in fact- when he gets everything on his terms. Villains and adversaries allowing this to happen is, in my eyes, some pretty poor DMing and quite possibly metagaming, depending on their intelligence and the resources available to them.