Player Design Rant: Stat Balance

I've repeatedly run into a problem with the RPG Maker engine that is causing me to rethink part of Harem Collector's design and balance. It might result in me changing the way that buffs work entirely.

RPG Maker uses eight basic parameters that you're probably all familiar with from HC's status and equip screens. They are:

Max HP (I've renamed to "Health" or "<3")
Max MP (I've renamed to "Mana" or "8)")
Attack
Defense
Magic Attack (I've renamed just "Magic")
Magic Defense (I've renamed to "Resist")
Agility
Luck

Most of these seem pretty self-explanatory, but in reality they are severely limited in how they function inside the engine. Attack, Defense, Magic and Resist only do anything because I edit the individual damage formulas of the various skills and attacks- they have no function outside those damage calculations. Which is fine, I have total control over what they do and can easily balance them with respect to one another. Max HP and MP are similar- they only count down how long it takes for a character to die or be unable to cast any spells so I have full control over how they're used.

The odd ones out are Luck and Agility, and it's these two stats that cause me no end of balance related grief. Agility determines initiative within combat rounds, the likelihood of escape in combat (which I don't use) and the likelihood of being surprised/having a preemptive attack (which are only calculated in random battles, which I also don't use). Not exactly the kind of thing battles are won on. Luck is even weaker, only being used to resist debuffs and added states. A high Luck can even be undesirable in this regard- it adds a resistance chance to all states, including Martyrdom, Stealth, the various Rages, Resistance Bonuses, and positive states from items such as Sugar Rush and the elemental weapon bonuses from things like Contact Poison and Alchemist's Fire.

This leaves me with something of a conundrum. For example, why would you ever cast a Cold spell if you had any other option, elemental weakness notwithstanding, if all the added Agility debuff does is make a given enemy act last in a round?

I've tried to address the weakness of Luck by adding a damage bonus equal to the attacker's luck to all attack damage formulas, but that doesn't seem quite enough. What I'd like to do is tie some of the game's ex- and sp- parameters into your Luck and Agility, specifically granting extra critical chance and critical evasion to Luck and extra hit rate and evasion rate to Agility, but I have no idea how to begin doing that. Help in this regard would be appreciated.

Anyway, just wanted to rant about a problem I have with the engine- and something you should be aware of if you're going to use RPG Maker yourself.