|Martial, Martial, Martial!|
Me and some mates were speculating about this and I'd be interested in hearing some thoughts. First off, the disclaimer - for purposes of this discussion, let's address martials & partials in a vacuum, no debating how this change might make martials suck even MORE in comparison to casters and so on.
Now what we were talking about was how in the combat game Strength dominated and could be truly exploited because high strength scores all but guarantee hits, even in circumstances when they shouldn't - the idea of a small creature dodging the attack of a large never really comes to fruition because the increased strength more than makes up for size bonus variation... so we came up with this as a sort of 'playtest' rule, applying it and looking at its ramifications, its ripple effects, as it were. That's one of the things I'm hoping to have discussed here, to help us not overlook potentially game-breaking issues.
The thought is that one's Strength bonus affects damage from thrown and melee weapons, including the standard 1.5 for two-handed and .5 for off-hand while one's Dexterity bonus affects damage from projectile weapons and light weapons (including rapier and whip). All attack bonuses are lost.
Now, this would carry over into monsters as well, with attacks still capable of dealing significant damage, but making those attacks less likely to hit. Combat would by necessity become longer, eliminating rocket tag to a degree and bringing AC back as a legitimate stat.
What are some of the other potential effects we might see?
Do you intend to tweak CMB/CMD in the same way?
As to your idea:
I think that it is by design that the first attack is more or less an automatic hit in higher level games and that iterative attacks are supposed to be the variables.
However, this only actually works with manufactured weapons since creatures with multiple primary natural attacks don't suffer from this and even for secondary attacks they can get rid of more than half the penalties on all attacks at the cost of a single feat. If anything this is probably what needs some adjustment.
If you worry about combats being too short, there is room to go from average to full HP in significant encounters; something I am testing in my group right now with satisfying results (the characters get more HP than usual as well).
To prolong combat you could go the other way and use Armor as DR rules by reducing damage instead of chance to hit; haven't tested this at my table yet but I will use that concept in my next low-magic game.
@Wind Chime: I think you missed the OP's premiss...