Smell/color is a poor method to check for contaminates, imho. If you want to be VERY precise, you can sent it off for analysis (like people do with engine oil). Aamsoil is quite good, no doubt--even with expense aside. But there's a lot more at play also. Are those highway miles or city miles? Are you a leadfoot, or do you baby-foot accelerate? Changing fluid doesn't inherently harm an engine or a transmission. The only times that has ever happened is when the engine/transmission was previously badly neglected, and the new fluid knocked particulates loose that caused damage. You can get by with the claimed 10,000+ oil changes that some oils claim too...but that doesn't mean it's a good idea. It has a lot to do with the blend of the oil, how quickly cleaning agents are consumed, etc. And a transmission filter is one of those "rarely changed" parts of a vehicle that can be quite full of particulates--even to the point where it starts requiring more frequent fluid flushes.

The most reliable method to read fluid temp is to have a gauge installed--permanently. If you are concerned with your transmission fluid temp (and keep in mind that there IS an optimum operating temperature and that a transmission can be operated below that under suboptimal conditions), consider adding a transmission cooler. Placement of said cooler will take some clever engineering, as the existing radiator cooling on these vehicles is already relatively poor; you don't want to obstruct airflow to the radiator at all. However, if you are using/making an aftermarket bumper, or not afraid to heavily modify the existing one, you can easily find placement options that will suffice.

p.s.
speaking of airflow, I've long desired a replacement hex-pattern grille that eliminates the "teeth" and has more peak CFM potential than the stock grille.