I think it's a little early to talk about team combinations. The level of playing will grow a lot in 2-3 mounts and i think casters like Annie, Ryze or Veigar will be used a lot combined with disablers mass ultimates and maybe 1-2 carries. If Annie for example farms solo mid and gets early lvl 6 she will really gang painfully. I believe a winning lineup in first serious games will come to something like: Annie, Ryze, Jax, Fiddlesticks, Amumu... Some similar kind of heroes may be included.. I'm just saying that most of mentioned lineups are simply picks of "stronger" heroes.. at first these picks will really own, but then teamplay will come in to place, wards... gangs.. and many different things

Jax, Yi, Taric, Zilean, Jungling warwick.

Jax with taric, yi and zilean solo- warwick jungles

Jax and taric harass/lane push like pros- yi goes meditate/e to begin with and just farms exp, zilean maxs cooldown refresher and speed/snare playing defensive.

At 6 warwick comes out to play- with a dragon down, extra solo lane- and an extra 8% exp you should be ahead in levels. Warwick ganks- the rest still farm- by 8-10 taric goes with yi to boom towers, jax goes with zilean and warwick to destroy kids.

Unless you are playing a good counter team- your mid/end game is win.