You need a wisdom of 10 + spell level to cast a spell of that level, so at a bare minimum, you'd want to have a 16 eventually, and start with at least an 11, 12 preferably.
Int should be 10-12 depending on point buy / rolls, it's not that important.
I think wis should be at least 14 starting. Ideally, you'd get a race that gives +2 wis and +2 str or dex (depending on if you're doing melee or ranged).
Ultimate Combat update: UC finally added some ranged teamwork benefits. A whopping total of...2. One requires BAB +6 (ie, level 9+), the other requires having a teamwork feat already. So it seems all ranged Inquisitors, if people even bother to make them anymore, will have the following teamwork feats:
Level 3 - Lookout (useful to anyone / what else can you take at 3?)
Level 6 - Enfilading Fire
Level 9 - Target of Opportunity
Level 12+ - Hell if I know! Hope the game is over by then?