We really cant even simplify the specs that much. Again, take efficiency for example. Is higher better, or lower? Depends on the goals of the user, space available, power available, etc. If we even could consider the efficiency rating published for subs as applicable (which, again, they arent), there is no 'better' or 'worse' efficiency. Is red 'better', or is blue? That is basically the same question as asking if a higher or lower efficiency driver is 'better'.
How about RMS? Again, depends on the individual situation the speaker will be placed in. If you have 500 watts to feed the sub, is one rated at 1200 watts a 'better' sub for you than is one rater at 600 watts? And are you even comparing subs that were rated similarly, since RMS is generally a thermal-based spec whose final published number is often adjusted by the marketing dept of the manufacturer.
Vas. See my above comment about Hoffman's Iron Law. Sometimes you'd want a sub with a relatively high Vas, sometimes you'd want one with a relatively low Vas. Again there is no 'better', except within the confines of each individual install's needs.
My recommendation on where to start in learning about speaker specs, is to learn what Hoffman's Iron Law is, and how it affects speaker performance and enclosure/power requirements. Knowing this Law is a good base to then jump into learning about the actual theil/small specs.