OKLAHOMA CITY — Oklahoma City’s Reggie Jackson has stepped in for the injured Russell Westbrook, and the Thunder have continued to roll.Thunder head coach Scott Brooks said Jackson’s improvement is not always evident, and not just because of Kevin Durant’s MVP-caliber play. Brooks said it’s hard for Jackson to stand out against the talented point guards he faces in the Western Conference on nightly basis. During a six-day stretch in January, Jackson matched up with Golden State’s Stephen Curry, Sacramento’s Isaiah Thomas, Portland’s Damian Lillard and San Antonio’s Tony Parker.“It’s just a position that, especially in the West, it seems like there’s 15 very, very good point guards,” Brooks said.Exceptional point guard play is one reason the West is 171-91 against the East this season.