1 goal in 3 would make him a good winger (12-13 league goals per season) but with his talent he should be scoring more, and if he's going to keep his place in the team when players like Sané and Jesus get going then he's going to need to not go 11 games without a goal like he has currently.
If you look back at the best wingers in the world, they all had a breakout goalscoring season at ~22 (Sterling's 22nd birthday is next week). Ronaldo went from 9 league goals to 17, Sanchez went from 6 in 36 to 12 (but in only 30 games), Ribery went from 1 to 12, Marco Reus went from ~10 to 20 goals a season. Pedro had his breakout season at 22 as well. Even Messi's numbers jumped up significantly at that age, from 30 a season to nearly 50.
It's a really common pattern and with a very good coach now to get the best out of him, constant gametime, a style of play which invites the wingers to get goals and settled in the club 18 months after his move, we should be seeing it from Sterling too.
15 league goals and 20 in all comps would be a good return for him. He started well this season but it's completely fizzled out. Hopefully tomorrow is the day that changes.
I do still completely believe he'll make that jump, I just want to see some movement in that direction because as I said, the other 2 youngsters will get going and he'll be left behind if he doesn't.