Basically, yeah, the thing with summons though, is that many casters capable of spending the full round action summoning could go for ending the fight via one of their other spells, instead of bringing a beatstick to the table. Hence, summoning's appropriateness depends on if you have access to Standard action or better summons.
Consider this also, a damage soak needs to have abilities to well...soak, prevent or otherwise mitigate damage, as well as the ability to draw fire. A d10 is only on average 2hp per level higher than the d6 rogue, AC alone doesn't do a lot to mitigate damage when its all or nothing, if a lucky, high damage attack gets past it, it goes through unmodified.
Compare rangers and barbarians. One comes with a free, disposable meatshield that is easily replaced, and the other has a d12, and the ability to increase hp temporarily(so healing can be deferred to post battle), as well as weak damage reduction. Both can take the same feats any fighter might take, and indeed Rangers have an edge on offense there, in that they get two weapon or archery styles regardless of the prerequisites(Being able to go TWF without needing to pump Dexterity is very good, and the archery feats means you can focus on ranged combat effectively even if you substitute ability scores(Zen Archery or Power Throw), not to mention the perks of fighting a Favored Enemy. Meanwhile, barbarians get a bonus that'd apply to practically every sort of melee mayhem while raging, and generally have enough uses to rage every fight.