In terms of style, the best I can come up with is the Argentinian Coutinho or Leon Osman with the ability to shoot. Intelligent, good dribbler, small, quick, great touch and awareness, good movement, hits a mean shot too. Reading of the game means he often ghosts into good positions or finds the space.
Not sure I really get the inconsistent tag, this year he has taken a more prominent position since Payet left and he's easily been one of their best players. Payet was a hard act to follow, but Lanzini has done well. Goals wise he has 8 in the league which is 3 more than our 2nd highest, in terms of creativity, only Barkley has played more key passes, in terms of passing only Schneiderlin has been more accurate.
There's a lot of reasons to suggest there's a really decent player stuck in a West Ham team, even if he looks a little lightweight and not so imposing. He's made comments that seem to suggest he's happy to look forward with West Ham, so suspect he won't be leaving or would cost too much, but can understand why we'd be asking, exactly the sort of player we have lacked this season.