Funny you should mention that. This is what I ended up doing for minion in 4e; well actually I gave minions HP equal to their average damage, which is 4 + 1 / 2 levels. The advantage of using this particular value has been that I almost never track minion hit points because they either go down on the first or second hit. Since I use tokens to represent minions, it's a simple matter of flipping the token to the bloodied side. That's all the tracking I usually do for minions.
Then you've got all the advantages of the monsters keying into the HP system, so there can be situations where a minion monster is dropped on a missed attack, or a fireball doesn't necessarily wipe off all the minions monsters from the field, or an NPC "minion" villager at risk of dying who needs healing.
A concept similar to this is what I think they should do for 5E.
In 4E, there are minion rules that change the paradigm. Some people like them. Some people do not.
But, the problem with having special rules for a type of monster is that it can mess up other aspects of the game.
For example, when the Battlerager first came out, that class basically ignored minion damage. The Battlerager could be surrounded by minions and it didn't matter. Here's an example of the one set of game mechanics interfering with another set of game mechanics. The Battlerager had to be errata-ed (and quickly).
But if minions follow the basic rules of all other monsters, then the problems that some people have with minions (and the problems with future WotC content forgetting about special rules) could be minimized.
HP: 11(1)
Could be how a given minion is statted. For DMs that want wimpy but not cardboard, they can use the 11 hit points. For DMs that want 4E minions, they could use the 1 hit point. This is an example of how both 1E to 3E can be merged with 4E WITHOUT having to add a special set of 4E module rules.
The same for damage:
Attack: Melee 1 (one creature); +6 vs. AC
Hit: d6+1(4) damage.
DMs that want to roll and want to hide the fact that these are minions from the players can. DMs that want to cut to the chase can use the 4E equivalent damage of 4.
Another advantage of this system is as you stated, the ability to remove special minion rules like "does not take damage on a miss". That's just another arbitrary 4E rule that doesn't necessarily make sense. Everyone else takes damage on a miss with a Fireball, but the minion is immune. Why? Because some designer thought that it was unbalanced throwing Fireball type spells at minions because they would always die with no real die roll involved. But when minions follow the same hit point rules as all other monsters, that problem goes away and so does the special rule needed to handle it.
