I have a couple 3e/d20 blogs I subscribe to, because even though I don't like 3e, it keeps a little variety and might occasionally clue me into something interesting. I had never explored many of the supplements to 3e, even stuff that appears to get mentioned a lot, like The Book of Iron Might. So I didn't know anything about the combat maneuvers system, other than it seemed to be really popular and people cite it as a great innovation. So today, one of the d20 blogs gave a summary of the maneuver system from that book:
The maneuver system (I’ll use the American spelling to stay consistent with the book, as it’s a game term) allows you to perform a wide range of combat techniques without taking a feat, but at the cost of a large attack penalty of -10 or greater. This penalty can be offset by taking drawbacks.I'm sorry, but that sounds like one of the worst designs ever. I can understand the appeal, because back when I played a lot of GURPS, I thought the enhancement and limitation system from GURPS Supers was really great; it added a lot of possibilities. But of course the downside was that you wound up doing a lot of fiddly accounting to tweak a power just right, looking up values for different limitations ("was 'DX roll to avoid' -20% or -30%?",) ambiguity in more free-form limitations, and limitations chosen for their point-value instead of thematic interest. This maneuver system, assuming the description is accurate, looks like it has all the same "benefits".
Lets say you wish to knock an opponent prone. You can do so, at the impossibly high penalty of -20 to attack. However, you can reduce that penalty by 10 if the maneuver provokes an attack of opportunity, by a further 5 if your opponent gets a saving throw or opposed check, and another 5 if the attack only knocks prone and doesn’t deal damage.
I've said before: the purpose of mechanics is to make interesting things happen. The maneuver concept certainly seems like an interesting thing, worthy of being added; but the tiny maneuver build system shifts focus to maneuver building, which isn't interesting and doesn't make anything happen. That's why my current maneuver system is "if you do this interesting thing, either the extra benefit only happens on a 5+ on 1d6, or there's a risk of a side effect on 5+, or both."