Something i've been considering doing in my HARP fantasy game is to disallow the expenditure of DPs to raise stats, but letting EARNED fate points be spent on them. but that would require a player to track which are earned and which he bought. OTOH, i've also been toying with the idea of handing out Adventure Points as a reward. the only hard and fast ideas i have that i'm trying to cover is basicly to allow the players narative ability (mine won't volunteer without some sort of mechanic). So John, who's playing Schwartz the Swashbuckler is fighting against two guards on a balcony in an in. John asks "is there a chandelier in reach?" I, having cleverly neglected to put props on the CIELING, reply with "probably not, but you can spend an Adventure Point to narate it". Maybe I'd allow a PC to use them to raise stats. Hmmm.
Here's how i think i'd do the above AP advancement thing. First, AP's get handed out for doing Adventurous and Heroic (note captials) actions, and VOLUNTEERING descriptives. Now, when a character does something that earns an AP (dosn't have to be successful, btw, just adventurous and/or heroic), he puts a mark by the stat or stats used. this is just a yes/no thing, it's not a count.
At the next level up procedure, the same pc can use any AP's left over to raise any stat or stats used, on a (tentative) 1 AP for 2 DP basis, with the same restriction of only allowing 20 Dp's worth of advancement (or 10 APs). DP's can be used for anything else as usual, and i might even allow AP's to be used as well, on the same 1 AP for 2 DP basis.
This makes the players EARN those extra DP's, AND gives the GM a bit of control over stat advancement.
I'll post this in the HARP fantasy forum as well.
Lord Damian