Is it even possible to have reasonable dicepools for D&D?

[Swordslinger]

The easiest way is just to convert to automatic successes after a certain number of dice.

So instead of 20 dice you have: 5 automatic successes + 5 dice.

The conversion rate is based entirely on your target number.

[Manxome]

30 dice might be a little too much. You mentioned flat tier bonuses earlier, what kind of automatic hits would you have to assign to a d6 at different points in the game in order to keep the dice pool size to a maximum of, say, 16 dice? Also if people are allowed to 'buy' hits at the rate of 1 per 4 die would would be the expected average in combination with this system?

The average number of hits is just the probability that a given die is a hit times the number of dice. For a TN of 5, as in After Sundown, that means you expect one hit for every 3 dice.

"Buying" one hit for 4 dice is like "taking 10"; it reduces your average result, but it eliminates the risk of a super-low roll, and so lets you claim automatic success on easy stuff.

For example, if you're rolling 8 dice at TN 5, you get an average of 2.67 hits and have a 53% chance of rolling 3 or more hits. If you buy hits at 4 per die, then you only get 2 hits--but you get a 100% chance of having 2 hits, whereas if you actually rolled there would be a 20% chance of rolling 0 or 1, so it's a good deal IF you're sure that 2 hits is enough.

If you lower the TN to 3, as in the second example from my previous post, then the average result is two hits for every 3 dice. So if you took one of those tiers and replaced 3 dice with an automatic +2 hits, then you'd have the same average result, and therefore the required number of hits for a "normal" difficulty would stay about the same--however, you'd generate a smaller spread of results, so the easy tasks would become easier and the harder tasks would become harder. Consequently, if you want to maintain the "<15% becomes >50%" rule, you'd also want to move the tiers a bit closer together. To keep tier 8 to a max of 16 dice (with tier 1 as 2 dice +0), you'd probably need to be adding roughly +5 or +6 in automatic hits.

If you wanted something like After Sundown's "buy a hit for 4 dice" mechanic in a system with a TN of 3, you'd probably want to allow buying a hit for 2 dice; each die is twice as likely to roll a hit, and therefore (basically) twice as valuable. In the example I worked out, that's enough for a tier 2, 3, or 4 to "buy" an auto-success against standard difficulty of one tier down, but you gradually fall further behind because buying is less efficient than rolling.

I don't want--say for an average curve--the absolute difference between tier 1 to 2 to be the same as 2 to 3. The only way I could implement this with a d20 was to make the bonuses and DCs exponential but that got out of hand pretty quickly.

I don't understand what you're trying to say here.

[Lago PARANOIA]

All right, I was able to come up with a curve that did everything I wanted to and at a reasonable dice-pool size (16 dice at the very, very top end, TN of 3) but this experiment has pretty much left me going 'why?' when I was done, since I was also able to do pretty much the same with a d20. I mean the dicepool system does have the effect of making people care a lot more about singular circumstantial bonuses and esp. automatic hits but at the same time it doesn't really have a lot of margin for bonus accumulation.

So back to square one. The whole reason why I was interested in this project in the first place was because I wanted to have a DC range that will accumulate a wide range of results that will lock unqualified people out AND has reasonable numbers. I am really unsatisfied about how D&D accomplishes by making people do high double-digit addition so I would like to get the numbers grokkably low. Would bell-curve rolling or Dragon Age's dragon die system help out with that?