Currently playing a Druid (Sentinel) with a Bear Companion and a focus on Summoning, though I resisted the temptation to multiclass Shaman for a Spirit Companion...
We used to joke about this type of build in 3rd Edition as "The Amazing Mister Wizard", since back in those days it was a lot easier to
completely fill the board with summoned buddies and pets and companions. All things considered, I've tried to avoid having my own summons reach quite into Litterbug levels, but it is tempting to have a bit of fun with it...
Defendus Interruptus can be pretty bad these days, with the real danger being, as noted, missing a trigger until after it happened, and then wanting to rewind and see how things would have actually played out.
In my last 3rd Edition game, I decided the party should go all out (it was a Planescape game), and gave the party approval to play the most absurd builds they could come up with, both in terms of mechanics and concept. Basically, a party filled with Freaks. When the 'normal' members of the party included warforged, faeries, half-minotaurs and undead wizards, it's hard for someone to stand out - but one player perservered. Enter 'Paulie', some sort of... feral, half-minotaur, anthropomorphic owl... monk? I think he had another template in there, but it basically all resulted in a pouncing charge with 20 or so attacks. And, of course, looking like some sort of bizarre, man-sized flying abomination.