[ginormous]

When I use a drum VSTi, it rarely sounds good on its' own. I usually have to play around with it. Here are some of my favorite tricks:

Multi-band compression -- different rates, threshholds etc., for different bands of EQ. I got a good bit of buzz removed from a snare using some downward expansion.

Layering samples -- Not enough 'tone' in a snare or tom? Layer some larger diameter tom under it. Trigger a sample player for that note-on specifically.

Room tone -- the old-school standby, as made famous by Hugh Padgham recording Phil Collins. Send the track output to another channel, set up your favorite reverb program (convolution or IR) as an effect. Short decay, maybe 500 ms or less. RePitch it down a few steps, and limit the living crap out of it. Keep it dialed back behind the original sound. I even threw in a tube distortion effect in front of everything else, to get some edgy breakup.

Edit: stack 'em. Get two romplers or sample packs, and see how well they blend. I got a killer R&B sound with two freebie romplers on top of each other.

Do some experimenting, but don't get lost going down the rabbit hole; it's quite easy to get overwhelmed with all the toys.