Simpler attacks at high level

[Biggus]

The 4th attack per round warrior classes get at BAB+16 doesn't often hit, and together with Haste and similar effects means a single round of combat at high levels can take a very long time, especially if there are two-weapon fighters involved. So I'm considering changing it so that instead of getting a 4th attack, at BAB+16 your 3rd attack improves from -10 to -5 (so at BAB+15 your three attacks are at +15/+10/+5, then at +16 they're +16/+11/+11).

In terms of hits per round, you average a little more against high-AC opponents and a little less against low-AC opponents.

Would this cause any problems? Are there any knock-on effects I'm not seeing?

[Mordaedil]

5th edition just decided to do away with declining attack bonuses for extra attacks and it worked out fine, albeit it comes with the caveat that they also have limited high BAB classes to 2 attacks, only allowing the fighter class itself to gain a full 4 attack routine, with the monk being allowed to do so as well by spending ki points, and they did that whole bound AC thing so your attack values and AC values aren't going to be too far apart at any given point.

But that's fifth edition. If you want to make more attacks a viable thing while maintaining a cap, an approach from the opposite end might work: Everybody can perform 4 attacks, but initially the penalty is -10 for each iterative attack, then at +6 it gets reduced to -5, at +11 reduced to -4 and finally at +16 reduced to -3.

[Incorrect]

Give everyone the same amount of attacks as normal, but they are all made with the same bonus. The highest.
That way you just roll your 5d20 at the same time and add the same number to all of them, that should be quicker.

Yes, that would mean that the martials hit more often than normal, but at level 16+ they need all the help they can get.

[el minster]

It depends the build if the last attack hits or not if you were a halfling 15 rogue 5 master thrower doing touch attacks it could very well hit

[PairO'Dice Lost]

The reason 3e moved to iterative attack penalties when AD&D had all attacks at the same bonus was that adding 1 extra attack at the same bonus of your previous N attacks is a very noticeable jump in hit chances and thus damage dealt, and they didn't want levels where you got an extra attack to be that kind of breakpoint because different classes get extra attacks at different levels. Adding in the penalty smooths the curve, basically, so if you don't care about that you can definitely remove the iterative penalty on one, some, or all attacks without breaking anything.