Well there's your problem. It's not trigger's fault really. It can only do so much with no clear transient man. There's a few different approaches you can take though.
First, start with the drummer. Make sure you (or whoever is playing) is hitting sufficiently hard. If you're hitting the toms like a vagina, then they'll suck. Consistent hard hitting will yield sharp nice transient. Toms have plenty of resonance and a slow decay, so their waveforms will always be a bit more of a pain, but if it's well played I usually have very little issues getting trigger to work.
2 - Automation of triggers parameters based on how a particular roll is played (detail knob, retrigger time, etc.)
3 - Edit the tom tracks. I've done this a few times when needed. Basically just cut off the waveform slightly after the transient, and totally get rid of what's causing the problem. You don't need the original audio, or can duplicate it, so it can just go. Then trigger won't see all the extra sustain and will trigger at the right place. You have to make sure you edit right though. Here's a quick example out of a session I'm working on atm. Looks kinda weird, but all trigger needs is that initial bit.
4 - Conversion plugins. I use Pro Tools, and a plugin called Massey DRT (not in VST form) to convert hits into either MIDI or audio clicks. Many times I'll use that to convert (which I did in these screenshots. You can see the kick and snare trigger tracks under the originals. These are tracks of converted clicks, with Trigger on them.) The converted Midi or audio clicks give trigger a super clear and separate transient to look at.
So anywho you can def make trigger work just how you want to man. Those couple tricks should help.
