Well, the idea behind dual wielding wands without ever using them is having two items granting INT boni and additional crit chance which with savage sortilage also applies to spells.
Sure, your characters have evasion without using AP or memory slots but you're also severely crippling their attack capabilities. The best defense is offense in this game (a dead or cc-ed enemy won't harm you), so actively spending points on leadership feels like a waste. So does putting points in weapon skills on wizards. In fact it's questionable for physical characters as well as damage boni from warfare and scoundrel are multiplicative while weapon skills are additive. In general it's best to raise crit chance (hothead, gear, fire runes and maybe some WITs if you can spare them) and stay with scoundrel after maxing warfare.
With wizards there is obviously no need for warfare (unless you're a necromancer), but apart from maxing INT you will need those attribute points for memory more than you need WITs.
Without item boni you can only add a maximum of 30 WITs to a character which is only +30% crit chance. Hothead (10) + quality weapon (20) + other crit gear (avg 10) already give you 40% at the cost of one talent point (assuming you have enough gold and patience to buy the items), without limiting your attack capabilities. Remember, WITs only increases the chance to crit but not the actual damage. STR / FIN / INT respectively increase your damage which is why it's better to max them before raising WITs.
IMO increasing WITs is more important for having at least one character in control of a battle immediately. And of course it's a must have for glass cannons, otherwise they never get to act
