Alternate racial stats

[RedFred]

Random thought. For game design, how unbalanced would this idea be?
When building a character, and rolling for stats, for any score with a +2, the player has the option of rolling for the stat twice (4d6 lose the lower die) and taking the higher result of the two, they may only do this if rolling for stats.

so let's say I play a mountain dwarf, with +1 wis and +2 con. instead of the +2 con, I decide to use the rule above, The first time i roll 2, 2, 2 and 3, so 7 total. the second time, I roll 3, 6, 1 and 5, so 14.

For the +1 score, the ability would be to instead the lower die in the set.
So using a dwarf with +1 wis. I roll first: 6, 5, 4, 2. I reroll the 2 and get 3. However, it's still the lowest so my score is still 15.

Thoughts?

[aimlessPolymath]

When I play with rolled stats, I normally am allowed to arrange them how I like after rolling (though your experience may be different)- it would be difficult to do this in that system given that the rolling would take place before I know how stats are arranged.

[RedFred]

When I play with rolled stats, I normally am allowed to arrange them how I like after rolling (though your experience may be different)- it would be difficult to do this in that system given that the rolling would take place before I know how stats are arranged.

The intention was actually they rolled, arranged, and then did the re-rolling thing, that could probably have been made clearer.

[Aeson]

I don't think it'd really matter, as far as game balance goes; high rolls aren't likely to get much higher (there's only a 4-in-216 chance to improve on a 16 with 3d6, for example) and low-to-middling rolls aren't going to go to stats your build really cares about. You might see MAD builds become a bit more viable since the reroll is a shot at turning a low-to-middling stat into a middling-to-high stat, but if you were planning to do something that cares about the value of the +2 stat then you weren't going to put anything particularly low there in the first place because there's no guarantee that that six will turn into a thirteen or whatever, and you probably weren't going to 'waste' a +2 on an attribute that you literally don't care about.

Also, if the idea is that the reroll replaces rather than supplements the +2, you've made the +2 a lot less valuable. Allowing a reroll increases the average value but not the minimum or the maximum, so whereas 4d6b3+2 gives me a stat between 5 and 20 max(4d6b3, 4d6b3) only gives me a stat between 3 and 18, and while I'd have to check to be certain I suspect 4d6b3+2 probably also yields a higher average value than max(4d6b3, 4d6b3). It might perhaps force the maximum attribute scores attainable at character generation to be more in line with those feasible under point-buy or found in arrays, but the way I see it rolling for stats is 'balanced' against point-buy and arrays (to what little extent it 'needs' to be) by the fact that there's always a risk that you'll do worse - possibly much worse - and probably aren't likely to do much better than you would with the arrays or with point-buy.