That has absolutely nothing to do with balance in either of the respective games. Furthermore, I believe that's the wrong way of looking at things. In AQ, you need armor, weapons, shields, and spells to defeat a variety of enemies; in MQ, you need chassis, arms, shoulders, and heads to defeat a variety of enemies (Not to mention you rarely have to change your equipment set mid-quest unless you're doing some sort of challenge, anyway).
In any case, weapons, spells and armors in AQ do not interact in the same way every piece of equipment does in MQ. Everything in AQ works as a single, static hit modifier, whereas MQ effects are rarely as static (proc rates in MQ have a much more drastic effect than they do in AQ), and pretty much everything in MQ is time-based. You cannot simply assign point values in the same way as in AQ, because a BoT of +10% Boost over 4 turns is far different from a flat +100% Boost for one turn, further augmented by the fact that missing in MQ can destroy your entire strategy (in AQ, everything is essentially treated equally and does the same thing; missing hit 1 will not totally screw you over where missing hit 2 wouldn't).
There is no syntax to attacking in AQ beyond dealing as much damage as possible in the fewest amount of turns through the use of Attack and/or your spells. MQ is different because the syntax of your attacks will definitely change the outcome. Classes, of course, are generally exceptions. Think of every Mecha in MQ as being a class, and every piece of equipment on that Mecha as its skills. It's more difficult to balance every piece of equipment in the same way every weapon is in AQ unless you want things to have nothing more than base/random damage.