Personally storm, my team is as follows (as of now):
lv. 21 Emboar (evolved pokabu)- Stats are nice, and a he carries some bulk. Currently, it has Nitro Charge, Arm Thrust, Smog, and tackle. With this moveset alone, I solo'ed the entire 2nd gym, and most of the first.
lv. 16 Yannappu (Grass monkey)- It's stats are nice and balanced so far, with it being just a little frail, BUT, it's my secondary sweeper for sure. It has vine whip, cheer up, fury swipes, and miracle seed as of now. It's also carrying a leech seed for a little extra boost to it's stab. Reason I always say that these two are all I need so far is because after a x2 cheer up, Yannappu sweeps EVERYTHING. Either Vine Whip OHKO's, or Fury Swipes 2HKO's. This thing is a monster to have at first.
My last poke is just a bidoof 2.0 for HM fodder, which is going to be it's only use.
The pert like pokemon of this gen im speaking of is Gamageroge, which is the 2nd evo of Otamaru. With the water/ground typing, and the excellent movepool I've seen so far, it will indeed make a great addition to the team. The other poke im looking at is Doryuzuu, the steel/ground. That thing alone has enough strength to boost it's attacks, and I plan to abuse the hell out of it's extreme bulk and attack stat. The next poke I'd be filling the team up with is Ono, the new Dragon. That's just a small tradition of mine that I usually grab a dragon for awesomeness sake(and it usually turns out great anyway xP).
With all that, my main team will equal out to 5 total pokes that can cover each others weakness decently enough, and possibly handle each gym either in pairs, or on their own. So having up to 6 pokes is still not a bad idea, it'll just depend on your teams composition. I personally dont mind having 2 HM slaves, but if I can make use of atleast one poke that has a HM (usually the water poke) I end up with just one HM slave anyway.