I personally don't really like Imp Trip. First of all, its got brutal prereqs. 13 int is rough if you are doing point buy, especially as a crusader since NONE of your abilities are tied to Int, but rather str, con, cha, and dex. That means you have incredible MAD, as you'll be spreading yourself thin by spending 5 of your precious points to get that 13 int, 6 if you go for 14 to even it out for the extra skill point.

Then, there's viability. Trip scales only on 3 factors. First is strength, which most monsters advance faster than you will. Second is size, which agian, most monsters will scale faster than you. Also, with size comes inherant strength bonuses, see point 1. Third is misc properties, things like stability, feats, circumstances, etc. This is one place where you can make up a bit of ground, but its still not overly promising.

Therefore, its hard to get a really high trip modifier, to the point where its possible to succeed more often then not. With failure comes pretty dire consequences. Your opponent has the opportunity to trip you, which a moderate chance to succeed, considering he just beat your initial trip check. If this happens, you have a choice. Either become prone yourself (bad) or drop your weapon (worse). If you do drop your weapon, you'll be somewhat useless in your desired role. This is all unless you take the Knockdown feat, but then you've invested 3 feats for a niche that only really works against things your size and has a pretty poor reward/risk ratio.

If you are going with Standstill, you are probably going to want EWP: Spiked Chain. Standstill's whole mechanic requires you to do enough damage that your foe can't make the save. In order to get this damage in an AoO, you need to have the 1.5x str and 2:1 PA you get with a 2hander at all times. Otherwise, when you strike with your spiked gauntlet or armor spikes, you aren't doing as much damage, and your viability becomes limited. Plus, then you have 2 weapons to split gold between for enchants.