I think you underestimate the power of the Monk. (I love how Star Wars-ish that sounds.

)
Three favored saves
4+ skills and interesting class skills
Hooge movement bonuses
Feat selection
DR bypassageness with Ki strike
... plus many, many more!
But that's just beating a dead horse. The monk is Tactical Mobility. Always and everywhere he is Tactical Mobility. You can't see that so much at the early levels, but when his movement is upwards of 50, you feel it. So in any situation someone needs to be somewhere
now, the monk is your man.
Tanking against Hill giants isn't your forte. And really, what's the harm with having your monk sit back and hold a conversation with the bard about the druid's animals while the druid takes care of everything. Not only would that be a neat role-playing scene, but it would teach your druid not to burn all of his spells so early, but to rely on his companions as well.
And, like the fighter, you can dish it out all day long, as long as your HPs hold up. The summoner druid can't.
[Regarding the heavy armor wearing fighter] Of course he's going to be obsolete in this kind of a fight. Put a heavy armor wearing guy in a big field, spread the enemies out and you expect him to perform? Never going to happen. His place is in dungeon hallways where he can stop up the enemy's front line. Dwarven defenders and Breach-gnomes were designed with this kind of terrain in mind. If they move outdoors, they're in serious trouble. Especially if they're fighting a monk with 90 movement.
So, love your movement. Love your tumble. Love your saves. And love the +18 total bonuses for your abilities. Love the Tactical Mobility.
But don't try to tank.