<<Too much thrust on one engine in real life has a much higher bad outcome than the other way around.>> (I can only assume you don't mean this is more hazardous than too little thrust on just one engine, which is what you appear to have written...)
How do you achieve more thrust on one side than in the SE go around case, one of the more hazardous of the "non standard" maneuvres?
No! Surely the point is the instructor was making (and I'm hypothesysing here) was that a running engine is a useful engine. It makes hydraulic pressure, electrics and thrust too. The harder scenario is surely one where all thrust (100% of it) is on one side, plus short of Hyd and a Gen (APU notwithstanding). This stuck thust scenario provides you with:
1) less asymmetric thrust than a single engine (if you were to shut it down) which must be safer and easier to handle.
2) Hyd and Elec that you would otherwise lose if you shut it down, making systems management easier.
3) much closer to full power for a go around if needed, again better than the SE case.
After landing it will give you useful reverse cancellable via the start lever.
Apart from which its a good chance that the stuck lever was caused by a frozen teleflex that will thaw at lower levels and restore full use of engine. Even so, it's Boeing built, so use all your strength to try to free it. You won't break anything (except your hand, or the ice blockage...)
Just an idea!