The GPO samples are much more flexible than they might seem without some experimenting. There's no need for special staccato woodwind samples since you can get them to >chiff< away as you need with the tools at hand.
Reegs certainly gave you an important tip about the velocity - the harsher attacks kick in at high velocity.
And the other ingredient is to work with the sample length. This is controlled via cc #21. You want to automate the length of the notes to be shorter for staccato and fast passages, so the tails of the notes won't linger longer than would be natural in those passages. You can always automate the lengths to return to the default setting of 50% or longer whenever you want, elsewhere in the project.
What problems are you having with legato in KP2? Do you mean the assigning of how sustain works for each instrument? - You know that you set that individually now, for each instrument. That way you can have a piano set on normal sustain, and the other instruments set for the special legato MIDI cc sustain, all in the same instance - unlike KP1.
But the rest of implementing legato still has to happen in your host environment, using a sustain pedal or inserting events.