You've made a HUGE leap in logic in this part. You took an off hand minor comment from Mearls that doesn't actually say quite what you want it to say, which even you admit is suggestive at best, and you've blown it up into a pillar to support a whole series of conclusions that are not otherwise well supported.
Sorry, that's not RAI. That's your own personal interpretation. The rules as written clearly say "If there are multiple observers, your Stealth check is opposed by each observer’s Perception check." That does not in any way match your conclusions. All of the wording in the skill is directed to being able to target individuals, and allowing for a failed check against some and success against others, and a stealth effect against those who you succeed against. And until we get an official clarification, we just don't know what RAI is right now (your guesswork based on suggestive off hand comments notwithstanding).
To add to this, WOTC_Mearls said:
"4. Remember that intelligent foes will share information. If one of the four hobgoblins spots a hidden PC, that guy can tell his allies where the PC is hiding."
That means that foes must be intelligent and share the information, not that if one sees you, they all automatically know where you are.
Later in the same thread, WOTC_Mearls also posted:
"One thing to keep in mind is that one of the big picture changes in 4e was to move stealth and hiding from spells to skills. In other words, the rogue or ranger are the best PCs for hiding, not the wizard with an invisibility spell.
The spell is still useful, but it is now much more limited and harder to use over and over again.
With that in mind, when you are DMing it's OK to be liberal with letting people use the skill. If a rogue wants to run from a hiding point, across a room full of monsters, and then hide again in a different cover position, that's OK. I've run it such that on a successful check, the creatures don't notice the rogue's movement, and it has worked out fine (my ruling being that since the player wanted to move stealthily, he was unnoticed while moving).
The interesting thing to me is that it makes creatures with high passive Perception scores valuable in encounters. I've been playing around with monster designs the promote a sort of "order of operations" for adventurers - take out this guy first, then this guy next - and high perception guys are an area I'm messing around with as "first step targets" to clear out space for the stealthy characters.
(If you played Return to the Moathouse at Origins, you saw a fight that operated this way in encounter 2. I won't say more to avoid spoilers, but there was one critter that you really, really wanted to kill first. I had one party ignore it and almost suffer a TPK as a level 5 party going against a balanced level 6 encounter.)"
You're picking out pieces of WOTC_Mearls' comments out of context to support a definition of RAI that is far from the intention that WOTC_Mearls is expressing. It's like picking out the words "thou" "shalt" "commit" and "adultery" and claiming that God told you to cheat on your wife.
And the minor action penalty on the use of stealth has no backing in RAW. "Stealth: Part of whatever action you are trying to perform stealthily" is pretty clear in its intent that it doesn't cost an additional action to do something stealthily.
I'm sorry, but what you've put together is a house rule based upon selective inclusion of information and questionable interpretation of the information you do include.