Hall of Heroes (Or Something Similar)

So I've been thinking again...
Currently there are three modes that all battles go through... 1) Magic - wizards shoot fireballs and whatnot, 2) next is archery, 3) finally melee mode.  I am proposing a new mode in between 2 & 3... hero combat.
Prerequisites & Layout
* Players may construct a "Hall of Heroes" once they pass a certain point (either in the build tree or beyond a specific net worth) at their town center and outpost(s)
* Each level of the Hall costs the same as a +1 castle upgrade such that a Level 1 Hall requires 4 runes, a Level 2 Hall requires 6 runes, ad infinium
* Each level of the Hall adds the ability to recruit 1 additional hero and increases the attack strength of said heroes by a significant margin
* When attacking another village, the player fills in the check boxes for the wizards and then on the same page enters a number in a text field representing the number of heroes dispatched to the enemy village
Mechanics
This system works similar to the Magic mode.  Attacking heroes engage whatever units are in a particular slot and do massive damage.  The combat system chooses a slot at random and the hero attacks.  If the hero forces a retreat, he survives the round automatically, otherwise, the hero has a chance of dying depending on the percentage of the opposing regiment that is still standing.  If there is a defending hero in that slot (also randomly assigned) then no damage to the defending regiment is done and there is a chance that the attacking hero dies.  On the chance that a wizard hits the slot opposing the hero, the hero dies automatically.  If the hero attacks a slot that has no troops in it, he simply wanders off to visit the local tavern for the rest of the battle.
Other Factors & a Few Notes
* Given the clan jumping issue discussed in other threads... I would "delevel" the Hall by one each time a player leaves a clan... regardless of whether they leave willingly or not... and with the runes involved not being returned.  Given the cost of an upgrade and the returns (I would love to see a level 10 hero be able to chase off a regiment of 100-150 knights and survive... and recall, there's 9 more of them), I really think that this would limit two things: 1) the current clan jumping happening in speed, and 2) groups of veteran players banding together late in the server to go traveling together (nobody wants to see a Level 25 Hall drop to Level 24... the rune loss would be brutal).
* Build times... tricky... I'm torn between the build times for castles and something more palatable (i.e. 1/2 to 1/4 castle build times)
* I originally considered treating Halls like any other building (i.e. players can build multiple halls, to do so each Hall has to hit Level N+1 where N is the current number of Halls)... the clan jumping penalty outweighed this.  However, if the clan jumping penalty is not a popular option, we can revisit the build mechanics