Is this amount of complication an aspect of every combat you’re in? I could see this number of variables maybe happening in the climax fight with the BBEG, but every fight?
Out of curiosity, how frequently do your players gain in level? How often do they gain new magic items that grant more than a static plus to hit? And how often do you use unfamiliar monsters? In most cases, one of the biggest slowdowns comes from either the DM or the Players looking something up in a book that they do not know off the top of their head. If your games advance in level more slowly than average, than there is a good chance that your players are more familiar with what their characters want to do.
When your player is resolving the actions of is summoned wolves, he knows exactly what they will do; They will attack at +X for XdY+Z damage, and resolve a trip attempt. Do that enough times across enough games, and both that player and the DM will have the trip rules down cold. Likewise, if your players often use the same buffs, they will typically have the modified values on hand, ready to go.
But complicated fights like the one you commented on can easily happen nearly every time. All that has to happen is for the game to allow for the '10 minute adventuring day', and for the players to need to roll out the heavy guns more often than not. If the only thing your summoned monster can do is attack and trip, running it is easy. But if it also has a handfull of spell like abilities, and inflicts ability damage on some attacks, or has attacks that also require a saving throw against something, things can bog down.
By this point in the thread, I think that everyone will agree that your experiences with 3rd edition combat are perfectly plausible, but many people have simply ran into unusually complicated combat. It really does come down to which parts of the game actually come up during play, and how familiar everyone at the table is with those particular rules.
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