Vyvyan Basterd said:
The main reason I believe a 50-point-buy PC is not "twice as powerful" is the premium cost point-buy places on higher stats. So, I would use your solution with a difference in ability bonus instead of ability:
For example, a character with stats 18 (+2), 17 (+1), 15 (+1), 14 (+1), 14 (+2), and 10 (+1) has a CR adjustment of about +0.8 (2+1+1+1+2+1).
I agree-- they aren't twice as powerful. It may, by stroke of luck, be true at 1st level, but the impact lessens as levels increase.
I like your solution as well-- which is also relevant when dealing with anecdotal evidence of supercharacters. Even at the same point buy, not all characters will be equal. The progressive pricing of point buy is designed to discourage really high (18+) stats, but it's certainly accommodating of lots of 14's. As point buy values go up, the barrier to 18's drops, there are plenty of points to shore up any weaknesses, and so a player is much more able to front load some ability scores.
With identical point buys, a fighter with one high score, one medium score, and 3-4 dump stats is more effective than a paladin or monk with the same point buy, but only one dump stat.
Again, the impact is lessened as levels go up.
But to suggest that a fighter with an 18 STR is not head and shoulders more effective than a paladin with a 14 STR is just silly. Against a typical array of opponents the fighter is going to hit more often for more damage.
Players tend to notice when they are sucking compared to the guy next to them.
the Jester said:
I would say, rather, that any DM who would have their campaign completely collapse because some pcs have good stats is not a DM that I would respect.
To be sure, this has as much to do with the players as the DM. It's certainly no fun to play a (randomly rolled) 20 point character in a group with a (randomly rolled) supercharacter.
(Feel free to assert an irrelevant anecdote about how fun it is to play sub-par characters; I consider that argument dead and settled circa 1981.)
Wiseblood said:
While you are certainly entitled to your opinion of what you feel is over-powered
I will continue to rely on expirience. (I would encourage others to do the same.)
There is certainly no shortage of people who prefer to rely on anecdotal evidence even when the underlying design principles are pointed out.
I could say with all conviction, for example, that giving a 1st level party a Deck of Many Things is a grade-A bad idea, and you can certainly come back with a story of how well it worked out in your campaign-- and we can both be right.
The OP seems like he leans towards worrying about balance, and wants to figure out the right solution.