Which is why Summon Eidolon, with it's duration of "longer than the combat will last" is a very, very good choice for one of any given Summoner's known spells. (after combat it's "hey guys, I need a ten minute breather here to resummon properly"). Ambush at night? Same thing. Etc.
Half casters with discounted spells. They actually get some spells earlier than wizards, have normal access to at least what would be eighths, get Gate as a SLA 3+CHA times per day, and are a CHA-focused class with UMD as a class skill (and if Synthesists, they can take a 1pt evolution to get an extra +8 to those checks). Not quite druid power, but pretty darned good. That gate especially... no material component, very high uses per day, 1min/rd duration without needing to go to the "negotiate and pay for a longer service" clause... Yeah. That's one of those "class features stronger than entire classes" abilities, right there. Dungeon crawling? No thanks, I have summons for that.EDIT: Also, they're half-casters, so they're far from "Druid broken".