Rules patch: Monster Mounts v8.1 (and chariots)

Much discussion has been had recently regarding the new "End Times" combined profile of models mounted on monsters. Here I wish to address how to re-balance the existing split profile mounted models, which, in conjunction with my previous patch on cannons, should render these models fully attractive for fielding and for the right reasons.
But before, I will rant. I'm so sorry. (please scroll down for actual rules patch please)

RANT START:
  Many have applauded that changing to combined profiles of monster mounts + riders is a good idea that streamlines the game. With the increased numbers of wounds, it is now easier for these important models to survive the first turns of cannon-fire, and thus justify their points worth in the game. However, I put forward that the problem was never in the mounts themselves, but in the rules for cannons (which affect both rider and mount unlike other ranged attacks, as I addressed here). Therefore, trying to fix the problem by changing something which was not the problem itself is bound to cause further disruption of the rules.
  First, combined profile models induce two major changes in how mounts behave: they benefit from all the defenses (armor & wards) of the rider, and (most aggravating) their attacks benefit from the bonuses of the rider. This is best seen on Karl Franz Ascendant's griffon attacks benefiting from Ghal Maraz's power, or Mortach Manfred von Carstein's dread abyssal's attacks being used to fuel the Magic phase. From my "roleplay-y point of view", this is quite unrealistic, and feels far too forced.
  Secondly, because combined profiles blend the defenses and attacks of the rider and mount, this creates unmanageable balance issues which invariably require these models to be pre-designed (such as special characters) and therefore limit customization (which is one of the key features of character creation in Warhammer). In this way, it will become impossible (at least under the current ruleset) to merge profiles as they exist in current rulebooks, as the threat of expanding the attack and defense benefits of the rider to the mount itself will make the game unplayable (10 attack vampire lord on zombie dragon with Red Fury, a 4+ ward and a 1+ armor?... and 9 wounds).
In my humble opinion, the rules were just fine, but I will try to address them a bit further.
RANT END

PROBLEM: Characters mounted on monsters (or chariots, which fall under the same rules) can be significantly vulnerable to be taken down directly (cannons, massed close combat attacks), which contradicts their high points investment. Characters mounted on monstrous mounts (such as elves on Great Eagles or Chaos Knights on Juggernauts) are more protected: they always use the highest of the characteristics between the two (rider or mounts) in addition to increasing the armor save as normal for a mount. On the other hand, riders of monsters/chariots gain no additional benefit other than an increase in armor, becoming more vulnerable and can be targeted freely in close combat by any model that can attack them.
SOLUTION: when models attack a ridden monster model (or ridden chariot), if they wish to direct their attacks at the rider they must first succeed on a roll of 3+ to get past the mount (or the chariot which is in the way). Roll once for each attack that you wish to target at the rider (even if they come from the same model). If they succeed they may target the rider normally, otherwise they must direct their attacks at the mount. Note that this only applies to attack allocation in close combat: abilities which affect a unit in base contact (such as the The Other Trickster's Shard) would still affect the entire mounted model (both rider and mount).
This makes the mount(or chariot) an effective defense for the rider, but the chance of attacks getting through is higher in close combat (3+ to hit the rider) than when the model is targeted by ranged attacks (5+ to hit the rider). This keeps close combat still the best chance to strike directly at the rider, as before, but helps the rider stay protected, as he is on a high vantage point and a huge monster is blocking the way.

The patch is incredibly simple, and the monster can still be taken down first (which tends to actually be easier than taking down some characters, what with armor and ward saves). This will leave the (previously mounted) character very unprotected and (if facing a ranked unit) mostly lacking in attack output to counteract the static CR such a unit can put out (and invariably might force the character to break).
Put together with the patch "cannons only hit the rider+mount on a 5+, otherwise only the mount is hit", which is also incredibly simple, I believe this puts these expensive but very cool looking models back as the centerpieces of your army.

There you go. Simple patches (hopefully) that tackle the initial issue at its heart (instead of switching the rules of mounted characters on their heads).